431132 Replacing Alertpay IPN with Zombaio Payment System

HI Guys! We have just launched our website www.downunderstudents.com. However our credit card processor (alertpay) are being problematic so we want to change over to ZOMBAIO.com. Our website and account has been approved. So we just need a programmer to quickly install the IPN code. I am not a programmer, however we currently have the Alert Pay system installed which is working fine! So hopefully it can be adapted easily. Zombaio provide detailed instructions on how to set it up. What should happen is this: Member on our site wishes to buy credit to spend on our site. They enter the amount they desire, and click submit. They are then sent to Zombaio - where they enter in their personal card details. Zombaio process the transaction, and if approved, sends the member back to our website and also notifies our website that the payment has been approved. Which then in turn instantly credits the member's account. Alert pay called this IPN (Instant Payment Notification) I am hoping that it is the same system with Zombaio and therefore requires little work. Programmer must be experienced and confident with this, as I am after a clean and fast job! Please note this is for an Adult nature site - that is already live and may contain some material on it.