Help needed adding a Graphic to GUI

HI all,
I am working on a GUI program and I need help adding a graphic representation to it, like a chart.

Here is my code:

/* Ike
   Write the program in Java (with a graphical user interface) so that it will
   allow the user to select which way they want to calculate a mortgage: by
   input of the amount of the mortgage, the term of the mortgage, and the
   interest rate of the mortgage payment or by input of the amount of a
   mortgage and then select from a menu of mortgage loans:

- 7 year at 5.35%
   - 15 year at 5.5 %
   - 30 year at 5.75%

In either case, display the mortgage payment amount and then, list the loan
   balance and interest paid for each payment over the term of the loan. Allow
   the user to loop back and enter a new amount and make a new selection, or quit.
*/

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.text.NumberFormat;

public class Mortgage extends JFrame
{
	// define window width and height
	private static final int FRAME_WIDTH = 400;
	private static final int FRAME_HEIGHT = 400;

// define text fields for amount of the mortgage, term and
	// interest rate
	private JTextField amountText;
	private JTextField termText;
	private JTextField rateText;

// define buttons to calculate mortgage payment amount and
	// quit window
	private JButton calculateButton;
	private JButton quitButton;

// define text area to display mortgage payment amount followed
	// by the loan balance and interest paid for each payment over
	// the term of the loan
	private JTextArea outputTextArea;

// term (in years) array
	private int[] terms = {7, 15, 30};
	// annual interest rate (%) array
	private double[] rates = {5.35, 5.50, 5.75};

// constructor
	public Mortgage()
	{
		super("Mortgage Payment Calculator");

Container container = getContentPane();

// set the Border Layout
		container.setLayout(new BorderLayout());

// create menu
		JMenuBar menuBar = new JMenuBar();

// Mortgage Loans menu
		JMenu loanMenu = new JMenu("Mortgage Loans");
		menuBar.add(loanMenu);

// add menu items
		JMenuItem term7MenuItem = new JMenuItem("7 year at 5.35%");
		JMenuItem term15MenuItem = new JMenuItem("15 year at 5.5%");
		JMenuItem term30MenuItem = new JMenuItem("30 year at 5.75%");
		JMenuItem quitMenuItem = new JMenuItem("Quit");

loanMenu.add(term7MenuItem);
		loanMenu.add(term15MenuItem);
		loanMenu.add(term30MenuItem);
		loanMenu.addSeparator();
		loanMenu.add(quitMenuItem);

setJMenuBar(menuBar);

// create labels
		JLabel label1 = new JLabel("Amount: ");
		JLabel label2 = new JLabel("Term: ");
		JLabel label3 = new JLabel("Interest Rate(%): ");

// create text fields
		amountText = new JTextField(10);
		termText = new JTextField(10);
		rateText = new JTextField(10);

// create calculate and quit buttons
		calculateButton = new JButton("Calculate");
		quitButton = new JButton("Quit");

// create panel
		JPanel panel = new JPanel(new GridLayout(4, 2, 5, 5));

panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));

// add labels and text fields
		panel.add(label1);
		panel.add(amountText);
		panel.add(label2);
		panel.add(termText);
		panel.add(label3);
		panel.add(rateText);
		panel.add(calculateButton);
		panel.add(quitButton);

// add panel at north
		container.add(panel, BorderLayout.NORTH);

// create output text area and make it not editable
		// and set font as "Courier New"
		outputTextArea = new JTextArea();
		outputTextArea.setEditable(false);
		outputTextArea.setFont(new Font("Courier New", Font.PLAIN, 12));

// and output text area at the center
		JScrollPane scrollPane = new JScrollPane(outputTextArea);
		scrollPane.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
		container.add(scrollPane, BorderLayout.CENTER);

// 7 years at 5.35% loan menu item click event listener
		term7MenuItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				double amount;

try
				{
					amount = Double.parseDouble(amountText.getText());
				}
				catch (Exception ex)
				{
					JOptionPane.showMessageDialog(null, "Amount must be numeric", "Error", JOptionPane.ERROR_MESSAGE);
					return;
				}

if (amount <= 0)
				{
					JOptionPane.showMessageDialog(null, "Amount must be positive", "Amount", JOptionPane.ERROR_MESSAGE);
					return;
				}

termText.setText(String.format("%d", terms[0]));
				rateText.setText(String.format("%.2f", rates[0]));
				displayLoan(amount, terms[0], rates[0]);
			}
		});

// 15 years at 5.5% loan menu item click event listener
		term15MenuItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				double amount;

try
				{
					amount = Double.parseDouble(amountText.getText());
				}
				catch (Exception ex)
				{
					JOptionPane.showMessageDialog(null, "Amount must be numeric", "Error", JOptionPane.ERROR_MESSAGE);
					return;
				}

if (amount <= 0)
				{
					JOptionPane.showMessageDialog(null, "Amount must be positive", "Amount", JOptionPane.ERROR_MESSAGE);
					return;
				}

termText.setText(String.format("%d", terms[1]));
				rateText.setText(String.format("%.2f", rates[1]));
				displayLoan(amount, terms[1], rates[1]);
			}
		});

// 30 years at 5.75% loan menu item click event listener
		term30MenuItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				double amount;

try
				{
					amount = Double.parseDouble(amountText.getText());
				}
				catch (Exception ex)
				{
					JOptionPane.showMessageDialog(null, "Amount must be numeric", "Error", JOptionPane.ERROR_MESSAGE);
					return;
				}

if (amount <= 0)
				{
					JOptionPane.showMessageDialog(null, "Amount must be positive", "Amount", JOptionPane.ERROR_MESSAGE);
					return;
				}

termText.setText(String.format("%d", terms[2]));
				rateText.setText(String.format("%.2f", rates[2]));
				displayLoan(amount, terms[2], rates[2]);
			}
		});

// quit menu item click event listener
		quitMenuItem.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				if (JOptionPane.showConfirmDialog(null, "Do you really want to quit?", "Quit", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_OPTION)
				{
					System.exit(0);
				}
			}
		});

// quit button click event listener
		quitButton.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				if (JOptionPane.showConfirmDialog(null, "Do you really want to quit?", "Quit", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_OPTION)
				{
					System.exit(0);
				}
			}
		});

addWindowListener(new WindowAdapter()
		{
			public void windowClosing(WindowEvent e)
			{
				if (JOptionPane.showConfirmDialog(null, "Do you really want to quit?", "Quit", JOptionPane.YES_NO_OPTION) == JOptionPane.YES_OPTION)
				{
					System.exit(0);
				}
			}
		});

// calculate button click event listener
		calculateButton.addActionListener(new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				double amount; // loan amount
				int term;      // number of years
				double rate;   // annual interest rate in percentage

try
				{
					amount = Double.parseDouble(amountText.getText());
				}
				catch (Exception ex)
				{
					JOptionPane.showMessageDialog(null, "Amount must be numeric", "Error", JOptionPane.ERROR_MESSAGE);
					return;
				}

if (amount <= 0)
				{
					JOptionPane.showMessageDialog(null, "Amount must be positive", "Amount", JOptionPane.ERROR_MESSAGE);
					return;
				}

try
				{
					term = Integer.parseInt(termText.getText());
				}
				catch (Exception ex)
				{
					JOptionPane.showMessageDialog(null, "Term must be integer", "Error", JOptionPane.ERROR_MESSAGE);
					return;
				}

if (term <= 0)
				{
					JOptionPane.showMessageDialog(null, "Term must be positive", "Amount", JOptionPane.ERROR_MESSAGE);
					return;
				}

try
				{
					rate = Double.parseDouble(rateText.getText());
				}
				catch (Exception ex)
				{
					JOptionPane.showMessageDialog(null, "Interest rate must be numeric", "Error", JOptionPane.ERROR_MESSAGE);
					return;
				}

if (rate <= 0)
				{
					JOptionPane.showMessageDialog(null, "Interest rate must be positive", "Amount", JOptionPane.ERROR_MESSAGE);
					return;
				}

displayLoan(amount, term, rate);
			}
		});
	}

// Display the mortgage payment amount followed by the loan balance and
	// interest paid for each payment over the term of the loan.
	public void displayLoan(double amount, int term, double rate)
	{
		int months;               // total months
		double monthlyRate;       // monthly interest rate
		double monthlyPayment;    // monthly mortgage payment amount
		NumberFormat nf = NumberFormat.getCurrencyInstance();
		double loanBalance;
		double interestPaid;

// calculate total months
		months = term * 12;
		// calculate monthly interest rate
		monthlyRate = rate / 1200;
		// calculate monthly mortgate payment amount
		monthlyPayment = (amount * monthlyRate) / (1.0 - (Math.pow(1.0 + monthlyRate, -months)));
		// set mortgage payment amount in output text area
		outputTextArea.setText(String.format("Monthly payment amount: %s\n\n", nf.format(monthlyPayment)));

// append header for Month, Loan Balance, and Interest Paid
		outputTextArea.append(String.format("%10s %20s %20s\n", "Month", "Loan Balance", "Interest Paid"));
		outputTextArea.append(String.format("%10s %20s %20s\n", "-----", "------------", "-------------"));

// for each month, display Month, Loan Balance, and Interest Paid
		loanBalance = amount;

for (int month = 1; month <= months; month++)
		{
			// calculate monthly interest paid
			interestPaid = loanBalance * monthlyRate;
			// calculate loan Balance
			loanBalance = loanBalance - monthlyPayment + interestPaid;

outputTextArea.append(String.format("%10d %20s %20s\n", month,
				nf.format(loanBalance), nf.format(interestPaid)));
		}
	}

public static void main(String args[])
	{
		// create Mortgage class object
		Mortgage mortgage = new Mortgage();

// set size of window
		mortgage.setSize(FRAME_WIDTH, FRAME_HEIGHT);
		// make window exit when closed
		mortgage.setDefaultCloseOperation(EXIT_ON_CLOSE);
		// make location of window at center of screen
		mortgage.setLocationRelativeTo(null);
		// make window not resizable
		mortgage.setResizable(false);
		// make window visible
		mortgage.setVisible(true);
	}
}

What I need to know is where in my code would I add a graphic and what code would I use to add it.

Thanks in advance for all help.

IKE