overheating problem

I have a 1996 Oldsmobile Aurora with about 75,000mi. It was having problems overheating before and i notice it leaking underneath towards the front of the car. So i brought it in to be looked at and they claimed there was a hole in the radiator, the passenger side fan was blown and that a fan relay needed to be replaced. Well i took the car home and ordered the parts i needed. I went to pull out the radiator and it was fine but since i had it out i replaced it anyways. I also replaced the passenger side fan which was indeed blown and also replaced the relay. Well the fans worked great. I took the car for a ride and everything seemed fine but it was also in the morning and it was about 70 degrees out. Well when i got out of work it was around 90 and I barely got home before it overheated! This time i noticed it was leaking from the rear of the engine bay!! Could this possibly be a freeze plug?? I checked the waterpump and thats not leaking! My other thought is maybe its the thermostat?? Any thoughts would be great. Thanks

hey nevermind on the problem. Had a chance to jack the car up today and noticed that it is leaking from the bottom of the waterpump so looks like i will be replacing that!! thanks anyways