Wireless and Me: I don't understand this crap!

[Tasoth]

Recently, I finally got my belated( two years) graduation present: A high quality PC. It currently resides in my room, which is where I am typing this post out. Obviously, the title tells you how I'm connecting to the internet: A wireless network. Fine for web browsing and what not, but whenever I fire up a game, I get temporary spikes, or quite possibly, loss of connection that happen for a couple seconds then go away only to repeat again. This would no doubt be a by product of the network. My question for you supreme masters of computer hardware, is there a way to solve this?

Router: Linksys Ethernet B
Networking card: Belkin Ethernet G USB adapter

The router is located a floor below and I want to say roughly twenty or so feet on the horizontal plane from my computer. Is it a single problem? If so, is there a way to boost it? Or am I SoL?