Macbook Pro 15 mid 2012 - not able to solve overheating
I understand your concerns (justified or not), you love your Mac and want to keep it alive as long as possible.

Here are some home remedy (Do it Yourself)-- (also available where you live).

If you want to keep your Mac cooler during HOT games, go to pharmacy and buy what they call a gel-pack (gel balení). Freeze it!

Then put it under your Mac with a towel in between (to prevent freezing).

That will provide additional cooling for few hours. Have second gel-pack if you want to continue gaming for 24 hours a day :)

As for your temperature reports, so far they look normal based on this example.


  Throttling
  
  This test wouldn't be complete if we didn't address the subject of
  throttling. Prime 95 and Furmark can extract the maximum performance
  out of the hardware. When both programs are run simultaneously, the
  core frequency drops (caused by Prime 95) to 1.2 Ghz. Running Prime 95
  alone, we measured temperatures between 92 and 104 degrees Celsius
  (197.6 and 219.2 degrees Fahrenheit), and the word "Throttling"
  flashes repeatedly in HWiNFO. Furmark on its own cycles through all
  available Turbo Boost steps. After about one hour, the temperature
  settled at a fairly consistent 85 degrees Celsius (185 degrees
  Fahrenheit) with the fan system running. We never measured above 100
  degrees Celsius (212 degrees Fahrenheit) with Furmark. This limitation
  might be due to the power adapter: in the above scenario, the system
  would require 86.6 watts - but the power adapter can only supply a
  maximum of 85 watts. Immediately after running our different tests, we
  subjected the system to 3DMark 06 and CineBench R11.5. The results
  were identical to after a cold boot.


The fastest way to quick check is to use the surface temperatures as shown here.