Create a Facebook app

This app/page have to do this: This app should make user to click on "I like" button. After this, will allow user to enter his data and a promotional code (voucher) which have to be validated. After code is validated user can upload a photo and participate on a draw, so he/she can get a gift if he/she is lucky. After photo is uploaded he will be redirected to a photo galery with photos of the rest of people that wants to win the gift on the draw. This photo gallery will be visible by all users, but only users with promotional code can upload a photo. This code will be the same code that is on a microsite. Will it be possible to use the same database? Will it be possible to get user data from our microsite instead of ask again user data on facebook ? So can our Facebook app/page access to database or our site? Thank you.