You should try equipping the orange charred ring, and a +1 ceastus for this fight. I had a lot of trouble with it myself, but I found the best strategy was to put on my trusty OCR and trade her blow for blow with kicks.
I tried to show her the kitchen and she ran away. But then, to my horror, she turned back around, took a running start, and rushed at me. This was followed up with a pivot backstab known as the "Thorolund Fisting," which dealt 8% damage and drained some of my stat points...but my soul level stayed the same!!!!