i want to build a mobile courses app for iphone android and windows phone

The e-learning application will consist of around 18 to 24 different screens. These are the expected features:
• Sign up / Login screen.
• Browse through subscription plans.
• Main Page / Find your Course.
• Course Description.
• My Courses.
• Payment.
• Rate and Review.
• Careers.

i have full document of what is needed in full details

please offer your price and the estimated finish time

thanks