You can modify your billing information directly within the control panel.
Go to the Manage Account in the My Account section.
Click Change Billing Information.
The Change Billing Information screen appears.
To Change the Billing information:
Enter the Billing Address details in the Billing Address field
Enter the Billing City details in the Billing City field
Enter the Billing Zip/Postal details in the Billing Zip/Postal field
Enter the Full Name as on Card in the Full Name as on Card field
Enter the Card Number in the Card Number field
Select the Card Expiration Date from the drop downs
Click Continue