Credit Card processing fro Joomla site

You bid on this project before and I chose the wrong person. The job is open again. I have a web site written with Joomla. So far I have PayPal as payment method, but I would like to add credit card processing. I have signed up with [login to view URL] . Here the instructions: [login to view URL] Here one of my pages [login to view URL] This page is really poor. I need a new page where a user can calculate the price. I am attaching a little VB6 project that contains the calculations. You would need to translate this into Joomla/PHP. From this new page I will have 2 buttons 1) Credit Card 2) PayPal. The current PayPal method has to remain working. There is an additional task: My version of Joomla is outdated and does not work with PHP 5.3. I need the site upgraded to 1.5.26 at least or better to 2.5