Hi!
I'm Johannes, a computer science graduate student from Paderborn, Germany. I have experience developing different kinds of Android apps (currently working on one for my masters thesis) and I think I can quickly deliver the medical app that you require.
Your requirements seem quite simple to me: the login screen (we should clearify whether the login on the backend server yields a cookie or an access token) with which the app starts and - if successfully authenticated the input for the medical data. Especially for the second screen I will provide you with different designs for different screen sizes, so that the app looks great and is user friendly on phones as well as on tablets.
A question regarding the backend: is the backend API and software already provided or do you need a solution for this as well? If so, I have built web services with different frameworks, like node.js, Spring (Java), Tornado (Python) or the Google App Engine.
About the 7 days: I think we I can get this done on one day easily, but sometimes it takes a few days until we have specified everything etc.
If you have any questions, please feel free to contact me any time.
Looking forward to hearing from you,
Johannes