of course its discontinued...
don't mark my words on this, but pretty sure that ring all the way around you should be able to drill holes and affix the ring back into place. you should probably confirm though. I installed a crl window in my van and did some documentation here
, starting with post #149.
the picture labeled as "outer" should show you what your window looks like under that ring. looks to me like you could drill holes anywhere around that perimeter and be able to re-screw it down. please do your research first though. I don't want to steer you in the wrong direction as im speculating that yours is setup like mine is.
also, like I said, if your window is square, you might be able to rotate the seam to the top and hopefully the screw holes end up someplace where the broken ones aren't. also again, don't reuse any of the screws if you are able to get them out. they are junk. go to the hardware store and get some quality ones and a bit specifically for those particular screws so you cant strip them out.
best of luck
EDIT: looking closer at your pix now that im not on my phone and you might have to remove interior pieces to be able to remove that black trim ring. hopefully the pix in my build thread can shed some light on your situation.