Make a video of family photos and interviews with the family about memories of your grandparents. Then transfer it to what ever form of video playback she has access to.
Buy a nice planter box and fill it with some of her favorite flowering plants.
Make a gift certificate for her with an IOU of some hours she can cash in for any chores or errands she needs help with. Put a credit balance of 24 hours on it, 2 hours per month.
Rent her favorite movie, make some popcorn and spend the day with her.
Make a 2009 calendar with family photos on each of the monthly pages then print it out and put it in a folder with magnetic strips attached to the back of it so she can hang it on her refrigerator.