a mug with your company name on it and gift cards to places near her...grocery stores, book stores, target, etc. all all good choices.
I remember leaving my part time job that I had before I left for college and everyone took up a collection unbeknowndst to me. they took me out to lunch and handed me an envelope. Most people would get a gift but they figured with college I could use the money and I could! I was so grateful.