If you think the A post has damage... get a body shop to estimate the repair and tell you what it needs.
If the door is damaged, you may be better off to dig up another door. It's allot easier to switch the door than repair it.
without seeing the damage it's hard to say what you need to do to fix it. You could make it worse if you go about it wrong.
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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurasic Park)
The Ogre's Fiero Cave (It's also at the top of every forum page...)