Window will not stay up.

Sounds like you need a new coil balance assembly. It's difficult to identify these while they're still in the window, but based on your photos I have a few suggestions for you to start with. Note that all components are sold separately; these are not available in complete kits.

See our 15-228 pivot shoe, 3/8" deep Series 165 coil spring, and 15-205 triple spring support. I strongly advise that you remove the original assembly to verify that these parts all match up, especially noting the spring size.