Window Lift Motor ('91 Deville)

My '91 Deville's front window motors have died, and I purchased replacements to replace them. I took the door panel off, but realized that the motor is not attatched to the metal door panel itself, but sandwiched between the door sides, with no bolts or anything to loosen. Upon doing exploratory drilling with a Hole Drill, I found the way it was connected, but it isn't a rivot, nor a bolt itself. I know I can drill it out, but how would I reattatch it?

Is there any places that can do this for me? I didn't realize it would be such a pain in the ass.

Any Ideas guys?

they will need to be riveted back together. bolts may come loose and cause it to be sloppy.

As Hawg stated, best way to reassemble is with 1/4" pop rivets. You could do it with nuts and bolts with red Loctite. You would have to be careful about clearance problems with nuts and bolts however.