I had my computer set up to do this already, connect my Appletv to my iMac so I can stream netflix and access my iTunes library, but something was changed and it doesn't work now.

I have DSL, plugged directly into my iMac. I don't need or want a router since I have a desktop.

I need help setting up a wireless signal from my iMac to the AppleTV and my iPhone (so I don't use all my data and can connect to "wifi")

PLEASE HELP! I know it's in the network settings and the guy at the apple store walked me through it once before.