Need help finding the right parts to replace this with.

Your balance assembly is made using the 15-180 Coil Balance Shoe. It is compatible with the Series 190 Coil Balance, which attaches to the shoe using the 33-073 screw. The coil is anchored in the window track with the 15-186 Coil Balance Clip and 15-182 Balance Bushing.

Alternate image for 15-180

To select the correct coil replacement for your assembly, you'll need to look for a stamp/marking. That number will represent the amount of weight that particular spring can support. 

If the stamps are hard to read, or there aren't any, take a look at the tutorial below for instructions on selecting the correct coil spring.