I'm with bigblock. If that section of the frame is actually bent/tweaked, you shouldn't have any problem finding a shop with frame straightening equipment that could un-tweak that one small section. You own repair guys could then replace the bolt on parts, although if your own guys don't have the equipment to do the alignment, you might be better off (save yourself some time and running back and forth) just having the frame shop do everything.
That must have been a good sized pebble is all I can say.