If you are looking to add an avatar, just post a link to your avatar image in this thread.
I have to add the avatars in manually until I have time and the resources to allow me to code a better avatar upload system.
All avatars are case sensitive, this means if you log in using an uppercase/lowercase letter and you registered with a lowercase/uppercase letter your avatar will show as the default avatar.
The avatar system is basic all it does is look for your registered name and replace the stock avatar with your own. But if your name differs in anyway the avatar will revert back to the stock image.