If that is going to be your payment options then I would rethink launching the site. Having such a limited abilty to buy IMO your toast from the beginning. Accept any and all payment options you can get. Tough enough out there and by limiting the number of ways a buyer can checkout just makes it that much harder.
Hard to recommend anything based on the post. You will need to research shopping cart software find one in the language you program in and then ask about specific carts.