I cant believe no one has helped you out on this so far... Well there are 3 ways you can do this
1: The barbaric way: Kill her, take the book, run out as fast as you can, find a gaurd and be prepared to pay around $2000 or so.
2: The intelligent way: Walk around and build up your speachcraft skill so its at least level 30, go back to her and either admire her to give you the book or taunt her to attack you.
3: The thieves way: Pickpocket her, if its there get it if its not shell attack you, kill her and pay your bounty off.