I am renting a place that only provides internet through wifi. My laptop has no problem connecting, but my desktop doesn't have a wifi card.I have a Linksys WRT54GX4 router. Is it possible for me to send internet from my laptop to the router, then to the desktop? I know that the opposite configuration works out of the box, where machines connected to the laptop via AD HOC wireless connection will have internet if the laptop is connected via ethernet cable.Both machines are running arch Linux. 
Internet through wifi
arch linux;wifi;internet
There is no need to involve the laptop. Just set up your router as a repeater (google is your friend if you don't know how) or buy a USB wifi dongle and connect directly.