Welcome to CEG!
If you can get to an Auotzone (outside of Calif.) have them pull the codes. Get the numbers, don't just rely on their interpretation. Many things can cause the light to come on, with the codes in hand you will know what to fix and how serious it is.
The Temp guage problem is usually just the sending unit. It screws into the coolant distribution manifold but may be a bit hard to get to.
Engine?
Miles?
