I doubt the cracks on the overhead door end of the building are new as a result of the tree falling, and from the looks of where the tree fell on the back end, well, it couldn't have been in a better spot. Most of the blow was directed straight down the solid wall to the ground. The overhead doors are awfully short which tells me the ceiling height of the lower level isn't all that great so it wouldn't really be worth much as just a single story garage. So much would have to be done beyond just knocking off the second story that it would be just as well to level the whole thing and start over. I don't think it's worth messing with beyond a new roof system and whatever partition walls upstairs might need looking after, and I'd be a highly suspicious insurance agent if anything more was sought.