Create a mobile app - Android to start with

Hi there, I need a mobile application with a very solid design. This is what the mobile app is about: It is a sports tipping mobile app. (I and 4 or 5 others) will post tips BOTH free and PREMIUM tips to the app (So there needs to be some sort of CMS to add the tips too). FREE tips can be viewed by anybody. PREMIUM tips can only be viewed once they LOG IN. To LOG IN they first need to SIGN UP. Sign up must not be done via in app purchase as the in app purchase limit is too small. Therefore, to sign up they must enter their credit card details in a form OR send to a secure website I have hosted where they can enter their information in. Once they sign up I will send them a username and password which they use to log in to view the PREMIUM tips. Furthermore, a person may register tips from Person A only so when they log in they should only see PERSON A's tips. They should not see PERSON B's tips. Also, it would be great if the user gets a pop up notifying them when the tips have been updated. It would be great if you could log in somehow via Twitter and Facebook too. Please let me know if you have any other questions. Thanks