I didnt have that much of a problem with her, I bash in with mace and shield and frequently cast paralyze spells on her and then hit her with my daedric mace until she rises, then I do the same thing again. Paralyze spells costs a lot of mana though so you better be prepared for that.
Another tactic I took her down with was when I was some sort of fighting rogue
I sneak up on her, deliver a thrust with the dagger, quickly change to a bigger weapon with shield and just block her out. Her sword is powerful, indeed, but if your fast enough with your weapon you might just be the better ^^