wireless network -help

While I was going through some support questions on the Apple site, I started reading more about Airport, and the whole wireless connection set-up.
I am not sure if I understand things correctly, so I am hoping some of you can clarify.

Right now I have the iMac connected to my wireless router, which I was using with my deceased Dell. We also have a PC laptop. I first understood airport to simply be a built in connection to a wireless network, and since my computer was right next to my router, I just hooked it up that way

Do I understand that if I plug the iMac into the modem directly, that the airport in the iMac would then replace the router? Then I could set up the preferences and security for the Airport wireless, and eliminate the router completely? Is this a good idea?
Will that also make it easier to netowork the laptop & iMac? Right now they just share a wireless connection.

No... the Airport Card within the iMac is simply a wifi card, giving you the ability to join your iMac to a wireless network. You still need a Modem and wireless router to broadcast the wireless signal.

Thanks for the answer.

In the same vien. I have an HP in my computer room connected to cable high speed. Is there somewhere I can find instructions to get aa wireless router and put my iMac in another room?

Thank you.