looking for the hopper window lock

See our 38-093L and 38-093R Hopper Cam handles. These look similar to your old lock, but please compare and see if you think these match up. 

I am afraid we don't carry a separate strike for these locks. To be honest, I wasn't aware they even used keepers; I've assumed that they locked into the window frame itself. See this old discussion for reference. It's possible yours had a unique setup. Unfortunately we don't carry an accompanying keeper in any event. I apologize for any inconvenience.