I agree with Karen. Try toys that make her work for treats. A Kong with kibble inside and peanut butter over the end. These things will only last a few minutes, but it will keep her brain busy.
Maybe get her a friend so she's not all alone when you aren't home? I know I shouldn't say that, because dogs are not cheap. But that's part of the reason we got our second dog.

Enroll in an agility class or flyball. Gives her a job and exercise.