As far as Wireless G vs Wireless N, I highly recommend going ahead and getting Wireless N. You don't have to get dual-band to get wireless - N, and so oftentimes, currently, you don't really pay much different go to N instead of only G. The good part about that? Also, Wireless N will give you a little bit of extra umph even if right next to the router. It won't feel super different for web browsing, but for video streaming, downloads, transfers between PCs, you can tell some difference.
I'd go with a D-Link
DIR-615 for the router - less than $50... as cheap as $30 at times.
For your Wireless card on a desktop, I've had lots of good success with these cheapies (wireless N):
Actually, I got one that was different, but that's the closest I could find on NewEgg at the moment...
Okay, they don't currently set it at NewEgg:
But, a couple other stores sell it... I suppose I'd go witht the 2 antenna deal right now, as it'll save $6, both support up to dualband wireless 6...
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"If to err is human, then I must be some kind of human!" -Me