Need shopping cart set up (API, Payment Gateway) to work with new merchant credit card account

I have? a website that sells products in various colors, option choices and shipping methods and are currently using a shopping cart (that uses HTML) that works with Paypal to collect payments.? We are getting a new shopping cart and merchant credit card account and need it set up. We're looking at using First Data Global Payment Gateway API? <[login to view URL]> The API supports the following languages. You can Choose the language you want to use for the API: • C++ • C# • COM Object technology (allows you to develop in Visual Basic, VBScript, or ASP) • PHP • PERL • JavaTM • Macromedia • ColdFusion • .NET I am the websmaster for the site now, and will need someone that is willing to explain to me how it works so that I can continue to maintain it. I only know HTML, CSS, some Java script, and have a very basic understanding of PHP. If possible, I would like be able to add a search feature to our website, but shopping cart and transition to accepting credit cards is the first priority.