We can close it - some things happened and now I have working Gallium3D driver.
What happened? First, I switched to Debian unstable repo and received update of xserver-xorg-core (and related).
Then - what's most important - i ran sgfxi which performed lots of operations, including removing junk after previous drivers.
Then - I removed uvesafb module. (It provided framebuffer for text console, but it's redundant with open driver,
and it's possible it caused fglrx crash, but I haven't tested it yet - since sgfxi author says catalyst 11.9 won't work with
xserver 1.11.1, but well, also to let him know if someone succeeds with it).
Well, it's still not as fast as fglrx, but it's fast enough to use for work. Definitely fast enough to run GNOME 3.
Always run install / uninstall scripts for fglrx driver - it leaves quite a mess, and reinstalling packages doesn't fix it.
Sgfxi leaves it's own mess sometimes, but sometimes it cleans it up.
With Gallium3D KDE allows to start all desktop effects and GNOME 3 runs smoothly. Transparency blur doesn't work. It worked only in one configuration - GNOME 2 + Compiz + fglrx. KDE runs way slower than GNOME 3.