there are various temp monitoring software out there. I use "msi afterburner" to monitor temps/voltage and use it to change my cards fan speed, core-memory-shader clock speeds. Same author of rivatuner I believe, so things will look the same.

Even though it is MSI software, it works on my evga gtx 260, so I am sure it will work on yours. just do not mess with the voltages that much or at all, could damage your card.
Evga also has a similar software by the same author of the msi afterburner, not sure if it has been updated recently though.