I've read a post somewhere from someone who said they actually found all of the XP 64 drivers they were missing on the Acer website. I'm just about to make a switch from 32 to 64 and I'm looking for that info again... If I find it, I'll try to remember to come back and post.
You will have to use the ATI Mobility Modder tool, for certain ( http://www.hardwareheaven.com/modtool.php
), but when I did this in the past(don't ask... :P), I was able to find everything I needed on the web.