M.S.
I don't think she is expecting a gift like you are---at least thats what it sounds like that if she gives you gifts you will have to give her gifts or you have to match her big gift giving. You don't have to do that. You can't really stop the gift giving unless you want to offend her and ask her to stop. Christmas is about giving---so don't worry about the tit for tat kind of exchange. If she gives a gift, thank her and move on. When it is time for the birthdays or xmas, you can decide then what you want to do if anything.
M