I've replaced the hose that was leaking the water out quickly. But the other problems still remain. Could a temporary fix be to replace the thermostat to keep the car from overheating? Perhaps take it out once a week to clean it of the gunk that is probably caked on there? One more question, is there any solvent that will clean out my engine of all the nasty gunk build-up?

PS The car is no longer running rough like it did when the leak happened this morning, though the CEL light is still flashing and it was flashing code 71 and 72. (cylinder 1 &2 missfiring)