You should bring a hostess gift for your hostess. Something that doesn’t have a shelf life, doesn’t need to be consumed immediately, and is a treat for the hostess. If you don’t know the hostess well (especially if you have never met her, don’t know her tastes or size), then you should stick with something generic that anyone would like.
While wine is a common gift, some people don’t drink alcohol. Boxed candy is something that can be shared later with family or friends. Flowers–especially a potted plant in a nice pot, rather than cut flowers–are usually appreciated.
If you give food or wine, your hostess is not obliged to serve it because she probably already has a menu prepared in advance. Unless your hostess has made it clear that she really wants your killer homemade cheesecake (or Junior’s Real Brooklyn Cheesecake), you should probably go for something else.
How about fancy liquid hand soap in a pleasant but neutral scent for her kitchen or guest bathroom?