I need a simple APP for my website followmyteacher.com

I have worked with a developer for the past year to create [login to view URL] and now I am looking for a very simple user friendly APP for the site. I only need it to do about 5% of the site. I basically need teacher, parents and students to be able to download APP in order to: Teachers 1. Send text message to students & parents phones. That will also come through as a push notification. 2. Teachers can see the drop down box of classes and student 3. Teachers can edit their profile 4. Register as a new user (all features are currently available through site. I have the code) Student/parents 1. Will receive a push notification when a teacher sends a message 2. Edit profile ( select teacher to follow) 3. Register as a new user