AppleTV problem

I just bought the new AppleTV and I set it up and everything with my Apple ID. All of my purchased music/movies shows up on AppleTV, but I cannot get my whole library to show up. My mac computer doesn't show up under the computers icon, even though I have home sharing turned on and I also changed my sharing preferences to share on whole network. I have the latest version of iTunes, and all of my software is updated. I don't understand why the AppleTV does not show my mac for home sharing. Any suggestions?