What kinds of toys have you tried so far? I cant get my 5 year old doxie to play with ANYTHING, but when I get the ball out, he goes nuts. And triss, my yorkie pup, likes anything that squeaks.
Does she like treats? Maybe if she gets excited over a treat, you could start teaching tricks.
Does she like walking on a leash?
Try to find some kind of stimulation that she enjoys, and go from there.