Need a Skilled iOS and Android App Builder

I need an iOS and Android app created from scratch for the website Upgrade to see actual info. Yuda Bands is a non profit organization that raises funds to pay for educational scholarships for students in developing countries to go to high school.

This app needs to meet specific specifications including:

-connecting with UPS API to auto create shipping labels
-link with existing databases
-Allow users to login via Google/Facebook and start a project
-Pick dates for the project
-Send automatic emails to multiple people
-Select a student to sponsor (Upgrade to see actual info/students) and add/draw info from a database
-Timed push notifications based on project dates
-Easy to share media (photos/videos)
-Link to social media accounts for easy sharing
-A help center with FAQ’s
-Leave reviews on Google and Facebook

We will need to be changing the app and working out bugs as we grow. So we need some that we can pay to build the app and be available on call to make changes.