So you're buying it back and walking away with $7700 to fix it?
My advice is start with CraigsList. It's cheaper to buy from private parties. If you can't find what you need, you'll have to resort to junkyards. While they are always my last resort (mostly due to prices), sometimes they are the only way. If you can, find a U-Pull-It yard. They sell parts cheaper since they don't pay someone to remove the parts.