IPad App- touchscreen vending machine

I have an interface that i have designed on powerpoint. the interface will be a touchscreen on a vending machine. It has about 12 buttons that are pressed, when each button is pressed, a graphic in the middle of the screen is altered slightly to illustrate the customers order. there is an opening screen (touch to start) the main ordering screen (as described), and then a final "shopping basket" screen.

i wish to produce this interface as an iPad app.