I haven't personally had to replace a damaged awning yet but a friend here in the RV park had one of his support arms fail last summer due to high winds. He had a mobile service tech assess the damage, called Dometic with a listing of the needed replacement items, and had the mobile tech install them.
Fortunately, there was not damage to the electrical wiring (power awning), mounting brackets, trailer sidewalls, or the awning material. It was simply replacing one of the support arms.
I think the whole repair, including service tech fee, was about $400.