I have a cerebellar hypoplasia kitty, too. Roger will be 2 this summer and he is the love of my life. They are such special kitties. He's not as severely affected as yours seems to be, in that he can walk and can use the litterbox just fine, but we also had some litterbox issues when he was a baby.
Here's a good website: http://www.chkittyclub.com/pages/home.html
There is also an associated Yahoo listserv, which you can join by clicking the link at the bottom of the page. Even if your cat turns out not to have CH, it sounds like her challenges are similar to those faced by CH kitties so you could definitely learn a lot from the folks in this group.