1993 Other Saturn Models Problems going up hills

My 1993 Saturn has lost all power coming out of first, I can't even try to spin out anymore. When it's cold, I have a little power, but when it heat up, the car goes about 2 mph coming out of first gear, the rpm raises but the speed is gradualy increasing slower. If it a steep hill, I don't even bother I just turn around. The probem is I give it gas, the rpm goes up but the speed gradualy increases very slowly. I was told to change out the o2 sensor, didn't work. I was told to put some gas treatment in the gas, didn't work. Now I was told to check exhaust system. Can someone help me please.