Welcome to the clan!! If you are talking the avatar under your name and you want one that a member has, just right click and save the image. Then go to your profile and upload the image as your avatar. If you are talking about the banner in our sigs, like Reform and I have (and others), then you can either make one or request one in the forums. Once you have one, you will need to host the image somewhere (some place like photobucket) and then paste that image link in the signature area of your profile.
If you still need help, like specifics on where to go, then just jump in TS and ask someone in there to help you out...we are all friendly...well...all of us except Nat!!!
Taz