My new boss is a confused man! Please help!?

I started a new job a month back. I was hired as a team leader in the PR department. Now initially while recruiting, my new boss painted a very rosy picture about my role etc. But when I got in, I found dynamics are quite different. There is another lady in the department who is junior to me and who is supposed to report to me. The only thing is that she knows the organization as she has already been there for the last 1.5 years. Now the boss depends on her for everything and gives me the only things which she cant do. He doesnt give me enough work and i sit twiddling my thumbs thro the day....meanwhile every one refers to this lady in case of all issues.....and the boss asks her to delegate the work to me..!! I am sick of this place! the guy is a confused person who doesnt know what he is doing! Help me what should i do? Is leaving the job a good idea? I feel like an idiot here! I tried telling him but he doesnt seem to understand!