In a way it sounds like you should decide whether you would like to give her a tip or a Xmas gift. The Xmas gift in my estimation might be a small amount bigger than your usual tip and that lets her know you were thinking of her. For instance it could be something based on something you have spoken about in the past, like movie or book gift certificates. Or maybe some kind of special teas or chocolates. Or even special hand lotions, etc. It's hard.