Computer running HOT is actually good thing - you don't need coffee mug warmer, just place it close to air exit.
On serious side, your computer can struggle with this game... especially if you run more then 1 client per gaming session.
Running
game booster can improve your computer performance, as it will shut down all unnecessary tasks/services.
Cleanmem does help with memory issues, but does not do much for CPU or GPU overheathing.
Also make sure you do basic computer maintenance - remove programs you don't use, clean computer using CCleaner, use the same program to clean registry and startup sequence and use defraggler (made by the same folks who made CC;eaner) to defragment your HD. Once done, restart computer. (always good idea)