Get a smaller size drill bit,{smaller then the screw piece thats stuck} drill out the hole, !make sure its smaller then the screw! then if u have a set of taps get them out and re-tap the threads to the hole, {make sure its the same exact size and threads as the new screw} then tap it and u will have the old piece out and a new set of threads to screw it into.

Trust me ive done it came out perfect