You CAN replace it, but why would you want to? Unless you want to continue to run your keyswitch, just unhook the keyswitch wires, tie them up out of the way (DO NOT hook them together or the engine won't start!) and remove said mangled bracket. You could also attach the keyswitch elsewhere on the bike, but lots of guys don't even mess with the keyswitch anymore.
If you want to replace the bracket, I'd ask for a replacement on here. Chances are somebody has one laying around they'll give you cheaply or for free. You never know!