Gallery2 shopping cart

All i want is some customization to the gallery2 cart module customization. Shopping cart functionality is alredy present int he cart module , All I want is a checkout with paypal functionality.. one should be able to select an option checkout and enter the billto and ship to addresses, and then choose an additional fixed price item and proceed credit for processing payment.. On the backend we need an interface for order management - very minimal feature set. This is not that of a daunting task for a php pro.. You need to be a real php and we are looking fro a quick turn around on this .We hiked our budget on this to $500 to make this intresting to others as well