My $.02, for what it's worth. I would get her a small yet thoughtful gift & a cute card. For the gift...maybe flowers or candy, or a movie or tv show on DVD show that she always liked. The card is very important to a woman (at least it is for me anyway). Don't get one too generic or too simple that she would be insulted by it, and not too mushy either.
Allow the kids to go a little more overboard for her. They will enjoy the time with you & feel as if they have done something very special for mommy. And she'll see your effort that brought it all together.
