because the temperature inside the CPU is way different from the cooling-rig's temp.
Yes, but if you measure both for a while you will see those are correlated and you may be able to derive a lookup table to map the inside and outside temperatures.
At least that will work for stable temperatures, and the cpu is not that stable in T.
Found this one after a google
didn't work for me but might work for your PC. Seems you need dedicated drivers...