OK, guys. I got hold of a genuine Apple Radeon 9600 Pro with 128 MB of VRAM (and dual DVI output, no ADC) and mounted it right away. It works OK, so I change the computer specs. Now it's got this, better card. And the best thing is - the price doesn't change! This one still can be yours for 50 EUR.

Here's a screenshot to prove the card is replaced.