I sent a nice thank you card, and that seemed to go over well. If you really want to get her something little, a candle is always welcome. She'll think about you whenever she lights it, and hopefully will think about you when hiring time comes around.
I would also do a card. In the teaching profession we get (at least in my building) loads of candles, mugs, etc. It has become somewhat of a joke in the teacher's lounge at school because there are only so many mugs you can have.
One idea you might want to consider is donating a book to the school library.