Your coolant reservoir is on the passenger side of your engine bay at the back. Its a big round bottle. You should be filling it with 50/50 mix of distilled water and G12 coolant. That is, as long as the G12 is whats in there now. It doesn't play nice with other types of coolant so you don't want to mix. See what color your coolant is now. If its pink, you need G12.
You'll also need to get the fan issue squared away or it will happen again.