iPad Music Recording App

I am looking for an app that I can take a pre-recorded guitar track and import into the app and record a drum track and mix the tracks together. Does Garage Band allow pre-recorded tracks to be imported and use?

In short, no. GarageBand is an ok app for workshopping ideas, but Amplitube (you need a little extra kit, Irig and guitar cables) is far far better. Cheap it's not but it is a lot better.

As for transfer, I have succesfully connected my ipad to my mixing desk, and used it to record each track seperatly, then mix using the desk. Hope this helps!