1994 Ford Explorer Radiator leak

I was driving down the road and stopped at a light. By the time it turned green, the engine was overheated and the power steering went out. Pulled over and popped the hood. There was a small crack on the top of the radiator and it was spewing coolant everywhere. Got some "Stop Leak" and put it in. Drove about one mile and it overheated again. Stopped and popped the hood again. All coolant had run into the overflow tank or leaked out. Overflow tank was full so thought it might be a clogged radiator. Power steering still out and cant start the car without overheateing. What should I do or what should I expect from my mechanic?