fix it. then sell it. then get one from JCR.
Fix the bumper throw on a nice coat of paint and put it up for sale. you'll be able to get a real good price for it, cause those are not cheap bumpers. I bet you'll be able to sell it and buy a bumper from JCR (or whoever) and maybe have money left over. it would be a lot easier than trying to make the TJ bumper work, and in my opinion I think it would look out of place.