Don't know what part to get.

Hello there. It looks like your coil balances may have snapped. Those are the spring tape mechanisms in your window track that regulate the window movement. The pivot shoe you show (the pivot shoe is the plastic block from which the window pivots, and which the coil balances connect to) is our 15-191 I believe. This shoe uses either 1/2" thick Series 160 coil springs, or the 3/8" thick Series 165 coil springs. You'll need to remove your old parts and measure the thickness of the coil tape to determine which Series you need. The video below explains how to remove and replace these types of coil spring systems. Let me know if you have further questions.