rear bumper question?

some idiot rear ended my 4x4 taco today im guessing they was backing out the parking space and hit my truck. my right passenger side rear bumper is 1 centimeter in and the left side is normal how can i pull that part straight?

 

It's an opportunity to get the All Pro offroad rear bumper. I plan to change all my bumpers when I get my vehicle so that minor fender bumbs won't mean a thing.

 

With such a small amount to move I am thinking a stringline and some brute force, I dont think heat would be necessary.