How to increase sound quality of GarageBand 1.3 exports from iPhone

I'm a new iPhone user.

I bought the iPhone over Android specifically to use garageBand.

So, I've created this song in GarageBand 1.3 on my iPhone.

It's got a a couple vocal tracks (from apogee MiC) and one guitar track (from apogee JAM).

I don't own a Mac or any other iOS device.

I want to listen to the song on an external device.

I know how to export the song to email, but the thing is, the m4a that is produced is very poor quality.

Is there a setting or a method that can be used to get better quality on the export?

thanks in advance for your help.

Bob