Yes your CPU is more than likely fried.
When you press the power button on your computer does the green light come on? Can you hear the HDD start? If any of this happens your motherboard should be fine, if the lights dont come on you may have a bigger problem.
Well the easiest way to find a complatible CPU is to get the model number of the Motherboard, If you can just post that on here id be more than happy to send you in the right direction. And yes the only thing you should need is a CPU.
This happened to me about three months ago, the power supply unit inside the tower unit had burnt out, I replaced it and everything is working fine. Try and get it replaced and see if you have any luck with it. If not it could be that the motherboard has been cooked due to a lack of air circulation. I hope you get this fixed