I don't know if you have an autozone in your area but i would recommend picking up a copy of Bruce Bonebrake's (I think) AC repair DVD.
You can order it online for 6.99:
HERE
You could also pick up a haynes auto A/C repair manual.
The nice thing about r134 is that the high and low side ports are different so you can not connect the guages wrong. Once you have the guages connected you can read the high/low side pressures and post them here. This will give you an indication of whats going on (ie low on freon, blockage in the system, etc.)
The typical high/low side pressures vary with ambient temprature so its important to have a thermometer. I used a thermocouple with my hand held multimeter, but just about any thermometer will do.