I had a simular issue but with the front frame, the shop had me put in a good k-member and the rear end had to be there, the good news is they charged me less than $150.00 to straighten the frame, basically 2 hours of work, I prepped the car exactly the way they wanted it so they only had to charge me for the time it took for straighten the frame... good luck, btw my frame was much worse than yours.