That was a hard hit. You will never pull that out with a com-a-long. The van will need to be strapped into a frame machine to even come close to pulling that correctly. DON'T try to push it out with a jack and bar between the rails. All you will do is further bend the rails.
I would suggest taking it to a competent autobody/frame repair shop. If the job doesn't have to be perfect you may be surprised by how cheaply they will do it for you. If you have everything stripped off and it is ready to go you could have it back in a couple of hours.
Mark