Should I change the rest of the support hardware?

If you're thinking of replacing one of your balances, it's best to at least order them in pairs. Otherwise the older balance will take more pressure and break. Inspect your pivot shoes and match them to our catalog of pivot shoes, I can only guess you may have the 15-045 shoe but if they look broken, then yes replace them. You can always send pictures of your window and it's parts for us to look at and double-check for you.