Try another salvage yard - maybe one thats a little farther away? Or you can check online also (not just ebay but sites that offer wholesale oem parts and online salvage yards).

You could also find out if anyone lives around you (check cardomain or just walk up to ppl that have your car and a diff bumper) that has a kit on their car and kept their stock pieces. I'm sure they'd let it go for a reasonable price.

BTW, what did you back into? And how fast?. . .maybe a bike is best for you

And if none of those work maybe you should just take it off (if its already falling off). Just say you're cutting down on weight and drag (dont forget the wing ).