As many other guys have stated here it's probably in your best interest to assess the corner and see how much obstruction there is. If there isn't a whole lot of obstruction or parts in that corner or in the side of the frame at all you can go to different various online vendors to include eBay and you can buy a repair tool either plier style or the die Style then you can do the repair following the manufacturer's instructions for the tool. Removing and gutting all of the parts to replace the shell is a lengthy process and if you can simply straighten the existing frame it's probably in your best interest especially if you are not possessing Advanced skill in small device repair. I wouldn't exactly say this repair is for novices.