Spring balance for 15 year old Boreal tilt window needed

The spring balance is about 1 1/4 inches wide by 2 1/2 long and 1/2 wide. The metal piece that pivots breaks over time with use. If that part could be purchased the spring balance would be fine. It mounts to window with a screw that goes through a piece of plastic that fits in the center of the spring. If I can find a replacement part I would like to replace between 10-20 balances.