What method did you use to apply the TIM? Try the small pea sized dab method in the middle of the die, and then make sure you are getting that heatsink mounted down tight. With thermal paste, less is better. Too much will have an opposite effect. And how warm is your office/room? A warm ambient will play havoc with your cooling efforts.
If your temps are still too high after re-applying paste and remounting the heatsink down tight (and that CPU should idle around 30-35C tops), then you should consider getting an aftermarket cooler like a Hyper 212 EVO.
The stock cooler is not good. It is supposed to be adequate, but even that is arguable and the EVO is cheap.
And I know this is a no brainer, but you did make sure the cooler's fan is spinning right? It happens.