Boss is stifling my career!

I’ve got a solid management role at a growing IT services firm, but alas, no one seems to see my potential. I have had conversations with my boss about my future, but she seems to think that I am doing just fine where I am and often deflects any discussions about career advancement. I’ve been in the same position for three years now, have reached and often exceeded my goals, and I think it’s time for a change or promotion. How do I get where I want to go when my boss is not supportive, and doesn’t listen?