My advice to you is to use your soul orbs and equip them to your weapons. Buy the best sword, staff, and bow, and manage when to use your potions when fighting her.
Does anyone know how to get your companion, The Twilight Zone? I beat death alone but got the bug. Is there some secret path I need to find? A post on here says take the follower with you till you reach death, but how do I do that? I can't get them off the main part of the map.