Thinking about buying the D-Link Wireless Gaming Router...

Ugh, subject line wasn't long enough. I have some questions. I am relatively a wireless newbie, but I can understand "geek speak". Let me explain my situation...

I am running three PCs in the same house. One downstairs, two upstairs. Max distance is 65 feet. Between the two upstairs, maybe 15 feet difference. We are on Cox cable, (preferred service) and currently on the Linksys BEFSR41 router. I am the gamer in the house and play everything from CSS to COH/COV. I don't really download that much, but my sister and father (other two connections) use torrents quite often. As such, I'm pretty limited to playing online due to the lag I get because of this.

So I considered this router because everyone seems to be able to benefit from it. I'm not expecting a groundbreaking acheviement, but I do know this router is better than what I currently have. But as for setting up a wireless network... I really am not sure all of what I need? Three pci adaptors for all three PCs? What about the switches/access points I see, do I need one of those? And finally, which should I buy then? I'm prepared to pay a total of $100 after I get these for each PC, but I'd rather not go over that.