Window part has come off

Here is the picture of the mechanism. there is one strap that should be attached by the tiny screw (pictured).

if you can send me the screw (it's broken) I could try to re-attach the strap - but so far I cannot find where it attaches to the frame!

Here's another photo. I can see where the broken screw would go. Only wonder is if repair can be made with a small sheetmetal screw or do I need to replace the strap attached to the underside of the window? I'm thinking the sheetmetal screw won't hold and the probblem will recur. Your advice please!