application for ios & android that has internet access

We are a group of personal trainers looking to create a simple way for us and our friends to manage our business. we would like this to be downloadable plus have access from the internet as well. the idea is anyone can use it free of charge you download it select if you are a personal trainer or client (we need to find a better more friendly name than client. if you select personal trainer you can create an account with your picture & skill set. once a pt has an account they can then create accounts for there clients to use to log in. once logged in the client only has access to there PT (its not a social network) a client can not create a client account only a pt can do this to have direct access to them and no one else. the client can enter two pictures a before and a current they can enter there height weight sex measurements. they can message there pt and there pt can message them but they can not message anyone else. client can see all available time slots on the PTs roster and select when they would like there session. the app would need to take payments to buy sessions (we are not sure on the easiest payment options for us to accept what are your thoughts?) they buy minutes with a minimum purchase of 30 minutes the price of these minutes is controlled by the personal trainer they can adjust them anytime they like for promotions with a minimum price of 50 cents per minute with no maximum. the way we make our money back and pay for updates would be threw a fee when minutes are purchased be it 3% or 8% or something along those lines. the pt will have the ability to adjust there calendar up to 12 months in advance showing what slots they have available on what days allowing clients to buy those times once purchases it will show up on this calendar who the client is if clicked it takes them to that clients profile where the pt can leave there own notes see there picture states and has an option to message them within the app. they need to be able to send pictures videos and text within this part of the app back and forth. the pt will get a notification when some one buys a session and a notification the morning of the session and 15 minutes before the session again. the pt needs an option to stop people booking session for the next 48 hours by clicking an away button this does not remove existing clients in this time frame just stops more being books to clients it will appear he is just booked out. I hope this makes sense we are not very rich but are willing to do what ever we can to make this happen as it can make allot of our friends life's allot easier. Kind regards, Jesse