WRT54G v8 random connection drops

So, I've had this problem for a while now, and I've kinda just been ignoring it. I've tried researching it, but to no avail. Here's my problem:

Randomly, at no particular time during the day, the connection from my WRT54G v8 router to my desktop with a WMP54G v4 will go from nearly perfect (like 80% connection with full 54Mbps speed) down to nothing. Sometimes it outrightly drops the connection, but usually it will go 54->36->24->12->drop. Sometimes, after it does that, it will reconnect after a few minutes. Sometimes I have to restart either my computer or my router for it to work again. When it does reconnect on its own, half of the time it will have a really crappy connection (like 60% at 12-24 Mbps) and often keeps on dropping. However, that isn't consistent either. Almost always, when I restart my computer/router I will go back to having a high connection % and full speed.
Another strange thing is that my laptop will always have a really high connection, even it is considerably futher away than my desktop. Also, my laptop, even in the same room, picks up another wifi network (a neighbor's) but my desktop can't even see it.
My setup is bad, but its all I can really work with. The router is in a room about 30-35 feet away, through 2 walls, on top of a wooden desk, about 10 inches from a corner. There is both a cordless phone and a microwave inbetween the rooms, but neither have caused problems. My desktop is using an internal card (I would love to buy something external, but I can't afford it right now). I have my xmit power set to 100% in the card settings. I am a little concerned about the placement of my desktop: directly behind it are about 15 different cables (power, connections, audio, video, etc...) and it is sitting probably 8 inches from the wall. Would it help to move it further from the wall (not that it can move that much) or try reorganizing the cables?
One annoying little tidbit is that, occasionally, my router won't let me into the settings through 192.168.1.1. I have to walk across the house, physically reset the router, and walk back to see if it worked. Another strange thing is that, although packet bursting is enabled on the router, I can't even force-enable TxBurst on my card. If I change the setting, it gets immediately reverted.

Is there anything I can do to keep my connection from dying randomly? Am I missing something? Most people I talk to just say 'thats how wireless works and youre SOL'. Would it help to just go buy a high gain antenna? Or is my problem more deeply rooted?