My thoughts would be to make a new stud for the existing frame,
Using small diameter round stock, thread the one end of the rod, and then tap the location on the window frame.
Or you could just use a small diameter rod, and drill the hole in the frame, and use JB Weld to hold it in place
If you are handy with tap and dies sets, this may work, as I had to make a new Emergency brake release rod for my 50, rather than spend to bucks on a used one. Go to a good old fashioned hardware store, and look around see what they have, that usually inspires the best in us.. Good Luck, and let us know, MIKe