Have you checked this thread already?

http://www.larian.com/ubbthreads/sh...&sb=5&o=&fpart=1

If you have, the way I beat her (after a few tries) was just gulping potions and running up to her, ignoring the Dreadknights and all that, and just hacking away. If you're in luck, she won't get a spell off <img src="/ubbthreads/images/graemlins/smile.gif" alt="" />