Basically you can buy a Wireless Router. Linksys is good. You can get it for around Qrs250 or less. Connect it like your normal modem and I can help you out too with the configuration.

I m not sure if it will work for you or not, but I created an ad-hoc connection using the Wireless USB Adapter in my Desktop to create JUST a wireless single connection to my PS3. It worked fine. Google : Ad-hoc internet sharing