Credit Card Acceptance Integration with Website

Our website, [login to view URL], currently uses PayPal to accept payments. We now have a virtual terminal (FirstData) and need to integrate it with the site. We will need a basic webpage made for the user to input all data necessary to process the credit card transaction and it will need to correctly integrate and communicate with the virtual terminal API. The site is undergoing a redesign at the moment and we will need to roll out the credit card acceptance feature at that time. The basic user info input page will be handed off to our web designer to put the final design on it. Appropriate code commenting will be necessary to ensure the success of this project in the final stage. Prior experience working with the FirstData virtual terminal API preferred but not required.