With the regulator properly secured begin bending the regulator in an effort to straighten the main frame. No two regulators bend in just the same way so you will need to bend it with your best judgement.

In these pictures you can see that in this case a flat metal piece was used to help pry the regulator body away from the motor at one point. It's just one example of places that the regulator can bend and how it can be returned to its proper position.

The metal of the regulators is fairly soft so it will usually bend without excessive effort. However, be thoughtful about how you bend it especially when bending the ends near the door attachment pegs. If pushed too far the metal of the frame can break at which time you'll need to source a good used regulator.

If necessary, the motor can be removed from the regulator to allow for that end to be held in the vice or otherwise manipulated. To do so, remove the three bolts holding it to the regulator and pull it away from the frame.