Create an App Engine project with GCM

We are looking to create a web interface that will interact with our existing Android app. It will be a very strait forward site. Users will need to be able to create an account and log in to that account. The site will need to send different small strings to the app over GCM. The app will do stuff and respond with a string. The site should then display this string to the user. Thats it, very simple but we are having a tough time getting started. We just need someone who can help us get this basic stuff, and we can take it from there. We need to do this as quick as possible. So someone who has already worked with GCM, App Engine, and Android in this way is what we need.