How to increase the fan speed on Radeon 4870x2

Hey!

I have just bought the Radeon 4870x2 from HIS! It's an awesome graphic card, but the temperature is a little high. It's about 60'C in idle and 80-85'C when I play a game. So I'm woundering, how do I increase the fan speed? I think I read somewhere that the default speed is 25%, so setting it to 45-50% should do the trick!
But I've heard that if you change the fan speed manualy, it will always run at that speed. But can you fix so it runs at ATLEAST 45-50% or MORE if needed. So it changes that it self, but never goes under the minimum %? Hope you understand what I mean.

If I need to download any program or do some changes in a program I already have, please explain exactly how.

Thanks for the help, I really appreciate it!

No need to post two seperate threads...but yes, use rivatuner.