First and foremost, notebook coolers will cool your system down - but as you already know - not by much. I would suggest continuing to use one, especially if your notebook has been used extensively since you purchased it.
Secondly, I would suggest taking it to a computer repair shop and maybe getting them to take it apart and clean the thermal compound up and replace it with some better gear. They could dust out the fans and the laptop in general, which should have it running much better.
You might see a 10-20C drop on load temperatures, which would be a huge gain on those high temperatures you're seeing now. Thermal compound dries up over time, and this can cause elevated temperatures - and so can dust build up, too.