Turn away from her before her attack finishes charging and dodge the other ones, but if you have an invisibility potion or skill, use it. You'll be able to sneak passed her, I don't think she's worth the trouble.
I was an assassin and had an invisibility skill. A friend mentioned using an invisibility potion to get passed her, I didn't ask where he got it, but I'd assume from a drop or store (if they even sell potions).
Never look at her when she's using the eye spell, and whenever she does a strafe run, run under her. The rest is just a matter of spamming. When you beat her, you get an emerald every time.
if your a priest just shadow bolt the shee out of her and take her head as a medal of honor and do naughty things with it but be careful cause u might cause your nuts to turn into stone