need a few balance replacements

I've got 3-4 wooden, double-hung windows in my house whose upper sashes slam open when I'm trying to close them.

I can't seem to figure out
a) what parts to order and
b) how I'm gonna get them back in- looks really difficult with these hooks on the upper part instead of screws.

Do I switch to screwing them in? Can you figure out what parts to order?

Thanks!