First of all I would like to as why would anyone not want to use the computer and still solve the problem? i mean there is not sense in saying that I want to do this and that without using computer, this seems much like a class quiz. :P
Secondly, the issue is that you need to use a converter application, you may be able to lcate one via google or in itunes, and if not available then you can ask some developer to develop one for you so that you can be able to convert your file to and from amr without touching the computer.
And secondly, you should check the profile setting, you ll be able to put an avtar, but do that only if you are interested in posting here, as your one post shows that you are just a passer by.
Hoping to hear back from you.