I've broken both before also... it really sucks, because after buying another one and installing it, I broke this one also. I was so pissed I punched a hole in my rear window and ripped it totally out. A little while later I gooped the window back in and bought a white hardtop for 200 bucks.
Honestly, Either drill into the bottom on the bar on the window and weld 2 studs into the top of the door so it sets in it.. or fab some holders out of metal. Good luck!