This isn't a technical issue it's more of an "I have no idea what to do thing."
Might want to try and put this in a status update or somethin next time. ^^
Anywayz, to activate a signature you're going to need the url for it, I suggest uploading it to something like photobucket.
After uploading it get the direct url, copy it, go to the signature area in your personal settings, click the picture/image button above the text area, and paste the url into the box. After doing this the image will show giving you a signature, save it and then you're done.
Wubsie's post in Does anybody know how to activate a signature? was marked as the answer