[ Computer Networking ] Open Question : how do i fix my home wifi?

a few months ago my wfi broke. i only have internet access on one computer now and that's with a cable hooked up to the router. On an ipod touch and other computers i still have signal, it still shows signal strength and so on, but other devices won't connect. A friend suggested i type in the default gateway into my browser and that took me into my bellsouth router page. (at least that's what i think it is) Can anyone guide me from there to help me fix my wifi? I have no clue what to do and need my wifi back asap. Any help would be greatly appreciated.