I assume the one you have now, is not the one you want to put up there?
Is your Avatar a JPG, GIF or PNG? You could trying converting from what you have now to one of the others, to see if it gets smaller.
Nope, the one I have now is just in the mean time. I currently have it in .jpg but I will give the others a shot.
EDIT: Rockin, got it. Thanks, it worked when I made it a .gif.