i would definately suggest a router/modem/wireless all in one, then you never have to crap around with your internet again (about $150), or just router/modem (about $99). another option is getting just the wireless adaptor that runs strait out of the one ethernet port of your modem. so it would go... wall into modem, modem into wireless, wireless into ps3 and your pc - this wireless is cheaper than any and would eliminate all chopping and changing. IF your pc doesn't already have wireless you can get wireless adaptors WITH usb pick ups for pc's without wireless network cards in the back... very cost effective, easy and can use as many things as you want. and no damn wires.
i got the modem/router/wireless. cost me $144, i got desktop strait into the modem, laptop and ps3 running wireless. but if i didn't want to spend that much i would've got the wireless adaptor out of the modem running laptop, desktop and ps3...