K.I.
T.,
Please do not quit cold turkey. You have done a wonderful thing to nurse your baby for so long. I nursed both my guys until they were around 24 months. (Really, only in America is nursing for only a few months considered normal. Most other cultures nurse much longer.)
My suggestion is that since she is only nursing for nap and bed time, to first distract her from the nap nursing. Hold her and rock her or walk around or whatever so she will go to sleep without nursing. After you get to the only-night nursing for a while, then try to get her to go to sleep a few times without nursing. Finally, then, pick a time and eliminate that final nursing as well. You can probably do all these steps in the course of a month gradually, and it will be less traumatic and a gradual, natural process.
Best wishes, and congratulations on your fine family,
K.