rear window regulator roller

don't know what exactly it is, but to quote a brother here, the do hicky that attaches to the thing a ma jig, fell off the whatchmaycallit!.

it appears a small guide that keept the rear of the rear roll up windown in a 72 swinger, broke and fell off. just the plastic. it seems like the mechanism just be removed to replace the small part. 1st is this a used part or does anyone sell them. 2nd. how do I take out he regulator without messing up more stuff as it is in perfect alignment now, just the part was old and broke the small shift it sits on is still there.

:D