Need advice for a new "N" wireless router

Folks,

Hoping someone can point me to a good source or give me some advice on what I do and don't need: I have a desktop computer plugged into my old wireless router, as well as four laptops around the house that use a wireless connection. I want to upgrade to a "N" class router. I don't know if I need/want a dual-band, as I don't do a lot of serious gaming (occasionally do some, though).

My main concern are the laptops get REALLY bad reception and speed, as the router is in the basement, and the laptop users are usually upstairs. So if I buy a "N" router, do I want/need dual band? Will that give me a stronger signal than a single-band? If the only bonus is that I can split off my gaming (desktop) pc from the other band, then it might be worth a few extra bucks if the other users will still get better reception/speed.

Also, do I need to buy new "N" USB adapters?

Thanks so much!
Steve

It seems clear from what I've read that to take advantage of N the wireless adapters must be N -- and preferably from the same manufacturer, for compatibility.

You can probably be confident that even the cheapest will work as they use the same chipsets as the better known brands.

But as this is a newer product I would stick with the famous ones as they will provide an assurance of future driver support.