I'll pick you a motherboard and PCI-E Wifi card... Also. a 600w Power supply will work fine but if you want to SLI your card soon, then you should go for 750W.
PCI-E Card: http://www.amazon.com/PCE-N10-Wireless-N-Network-Transmit-Interface/dp/B004ZMGBLQ/ref=sr_1_4?ie=UTF8&qid=1384673324&sr=8-4&keywords=asus+wireless+card
This is an x16 card, It goes into the top slow of the motherboard and will not interfere with anything. The antenna sticks out the back and for it has never caused any problems. Asus drivers are good aswell.
This is on a really good special offer, I'd pick it up, Even if you don't upgrade, more power cannot hurt. Also... This is modular so it'll make your case look nicer