Add Credits Script

I am using the Vodes component which gives credits that users can spend on a Joomla site. It was originally intended to be used with PayPal. I need it to work with another payment processor. I have taken care of most of the changes myself in regards to the front end and spending of credits, but need a programmer to create a [login to view URL] type script to handle the call from the payment processor's server after the payment is made. For example, when the customer completes a payment the processors server makes a call like so... [login to view URL];Identifier=User01923&Credits=50&TransactionID=1000028837&SiteID=738742&Hash=a8eec58efbad22acd6b50d173ebac40c&VISITOR_IP=127.0.0.1&CardHash=ab361c3a8h9e What I need is a script that handles this call (mainly the "Identifier" and "Credits" variables) and then adds the credits to the user's account.