Have you tried just getting rid of bloom but leaving SSAO and Light shafts on?
But HDR is often something gamers have issues with. Everything from Crysis 1&2, BC2, Valve games etc. And for each if there isn't an option to reduce bloom, there is usually a mod for it. I'm not a fan of bloom on any game, softens too much. TW2 looks great with SSAO and light shafts with bloom off.
So yeah, just sit tight and be patient. In the mean time you should search the net for good sites for mods. You should bookmark the Witcher Nexus, gamemodscore and Moddb websites for the time being.
http://www.moddb.com/games/the-witcher-2-assassins-of-kings http://www.witchernexus.com/
http://gamemodscore.org/forumdisplay.php/29-The-Witcher-2-Mods