Depends how bad the damage is, behind the door skin is a reinfored bar called the crash bar, if this is damaged it can be replaced as it is only a bolt on part, the door skins on mk5 golfs are also removeable, loads of t30 torx bolts so if the door frame is ok you can just replace this.
Jetta and golf estate door skins are different however, they have an additional swage line above the handle and a different shape at the bottom.