1994 Ford Mustang Heater not working engine overheating

My cars heater just stopped working now only blowing out cold air. The defrost system also isn't working properly. It does seem to be giving off a coolent smell. We thought it was the thermosate and changed it but nothing. The fan is the only thing keeping the engine overheating too fast. In a parked position car runing the cars heating reader doesn't register unnormal its when gas is aplied that the dile moves closer and closer to the red. After the car has run for a while and then is turned off the water pump leaks coolant. Is this normal? Any suggestions of what We should check next?