Add First Data payment processor to Virtuemart

We have set up Virtuemart on a website but only have Paypal payment activated. We have a merchant account with First Data which is the same as linkpoint or yourpay. We need assistance setting up payment processing for this payment method. We have our store id and customer ID, which is what we believe is needed to process payment. We cannot find the correct php file to use in virtuemart. We need help getting this to work. We would like this project completed within 1-2 days.