In the user control panel under edit profile, there is an area to post your signature

Just use the [img]url of image[/img] tag like you would in a regular post, then it will come up all the time! Do you have an image hosting subscription? (Places like photobucket and imagestation are free but photobucket I think has stopped signing up free members right now)

If you dont have a photobucket, I can host your sig on mine for now if you would like