I used the drivers that came with 10.5.2 to install Leopard but I can't change res and no QE/CI. I tried the Triatkis driver but all I get is a bright white screen at boot. I've heard a lot of people that got this card to work but I can't find a guide or anything...
Could someone please help?

Try this
http://netkas.org/?p=56

Copy to /System/Library/Extensions
Repair permissions and remove /System/Library/Extensions.mkext and caches
and Reboot

I already tried that Natit.kext but I installed it with Kext helper after I had ALREADY installed Triatkis.pkg
You think it might work if I make a clean 10.5.2 install without installing any drivers from the cd and then installing the new natit?

I made a clear installation.
With Transmac copied the latest Natit to Leopard.
After boot -s and Copy to /System/Library/Extensions
Repair permissions and remove /System/Library/Extensions.mkext and caches
and Reboot.
And had success.

Sorry the English