It looks like from the OP sig that he has a YM2210D. Fredricks has some good ROPs info on their site and I think they are the source for most of the Yanmar ROPs.
http://fredricksequipment.com/storage/rops-manuals/Family 4.pdf
Steve
Here is the mounting pic from Steve's link.
The ROPS appears to be mounted on the rear cover of the PTO, along with half a U-Bolt around the axle holding on the fenders. The bolts appear to only be in the cover, but you would have to verify that they don't extend into the transmission.
I assume that is the part number provided by Winston, Part number 194310-24350, although I don't see it online.
Anyway, talk to Yanmar about that piece. Is it available?
Perhaps you've been dreaming of a fancy new green or orange tractor, but I would hardly think this would constitute scrapping the tractor, just likely a pain to put in. Maybe you'll get some new bearings out of the fiasco.
Depending on the sheet metal damage, that could probably be repaired too.
Depending on what happened, you might also consider attaching the ROPS to all of the axle U-Bolts/nuts, (4 holes on each side), and send some photos and an explanation to Fredricks, if they manufactured the ROPS.