Her's a darn good price on a new OEM bumper

04 05 06 07 08 CROSSFIRE REAR BUMPER COVER OEM PRIMED : eBay Motors (item 390145851054 end time Feb-19-10 09:02:58 PST)

Personally, I wouldn't even mess with the insurance company. It happened in a parking lot so it's on private property. And they're not going to pony up for full MSRP of a rear bumper from Chrysler.

Also, the one on Ebay is primed. All you gotta do is paint it. ($200?)

For less than the price of a deductible, you're fixed. Go that route.