Mobile studio app?

hi guys,

Forgive me if this sounds noob, or has been covered in another thread, but I couldnt find any info on the forum so I decided to create my own!

I am looking for an app that has the ability to record audio (singing / rapping) from an input device, directly into the Ipad 2.

I know garage band allows mic input which is cool, but if the actual song isnt created in GB, can you upload a wav file to sing over etc?

I havent been able to clarify this as of yet and wondered if anyone else is doing the dsame sort of thing.

The scenario is, that some people send me mp3 or wav files that a re purely instrumentals, and I add vocals to them. Id love to be able to do this on the ipad with a decent mic.

Cheers!