1992 Toyota Corolla Dx overheating and leaking oil

I have a 1992 Toyota Corolla Dx I bought for 900$. It has 181,000 miles on it. I live in Michigan but this car came from Texas, it looked nice on the outside with no rust and all. But under the hood, it has issues! It leaked oil pretty bad, about a quart a week, but I put stop leak in it to stop it temporarily. I was driving it just fine, making sure all my fluids were topped off, until recently it started over heating! I replaced the radiator, thinking that would solve the overheating issue. For about a day it did, it stayed at normal temp on my gauge and the heater kicked out nice warm heat. It seemed fine, but that night it started overheating BAD! My brother seems to think that replacing the water pump will possibly solve this overheating issue, but I have a gut feeling maybe it's more than just that? The thermostat. And I wouldn't be surprized if the head gasket is blown or on its way there. Also, if I do replace the water pump, do I have to take off the timing belt to get to it? How should I go about this? How much should I have to spend? Thanks so much for helping me out!

Brandon
from Michigan