99 Seville backfires/misfires, losing power (will barely go up my driveway), running hot.

A couple of weeks ago it backfired real loud. When I opened the hood I noticed the radiator hose on the top left was leaking. On closer inspection I realized there was a big hole in the radiator where the hose was supposed to be attached. Thinking that the radiator must have been badly clogged up, I replaced the radiator but the car is still doing the same thing. Runs hot, backfires & looses power badly.