Hit a curb really hard and my alignment is really bad.

I drive a 2001 Honda Civic that has about 70K miles on it. This past winter I slid sideways in the snow and hit a curb really hard with my right rear wheel. The wheel is visibly out of alignment, as it's angled in towards the back of the car and out towards the front. I took it to a shop and they did an alignment check but said it's so far out of whack that something is damaged and just getting an alignment won't fix it. The rear tires are wearing unevenly and I really need to get this fixed. Should I take this to a mechanical shop or is it something that needs to be fixed at a frame/body shop?