you could buy her a nice photoframe - or bottle of perfume - or just spend a bit of time with her and take her out for the day (to a park or somewhere scenic)... just spending time with someone usually means a lot more than receiving a gift.
another suggestion; how well do you get on with her family or other neighbours; invite the birthday lady and couple of guests (other neighbours) for a meal at your house.
Does she like listening to music or watching telly? - a music cd or dvd perhaps could be an idea or a small hamper of some luxury goodies to eat/drink.
What about a tweve months Subscription to her favourite Magazine it will keep her going until she is 81. Cheers and happy Birthday to the Lady in question.
Alligator