Have been having trouble maintaining a connection.

So I've always had problems for a long while with my internet disconnecting randomly. Since I got this computer actually, but I'm finally fed up with it and am asking... Sometimes it lasts a while, up to an hour.. Sometimes it disconnects just a few minutes apart...and I've even had it disconnect twice in a row consecutively, as soon as it reconnected (which is always right away but its still a problem during gaming, downloads and Instant messaging.)
At first I thought it may be the distance between my computer and my mother's where the net is coming from, but my younger brother disconnects too and his room is right next to hers. Here's the weird part. Whenever our internet disconnects, it often does it at the same exact time. He and I would disconnect simultaneously. This would also happen with my nintendo Wii or my Nintendo DS, Disconnecting simultaneously with my computer, or with his if i was in his room with my DS.

Here's the weirdest part. My older brother's room is just as far across the house as mine is from the router, but he never ever disconnects, and his computer isn't as good as mine and is very slow. Neither does my mother with her laptop, even when she goes outside. I don't think its me overloading my comp to the point where it cant hold the signal either cuz sometimes all I'll be doing is IMing and I'll disconnect anyway and my DS can't be overloading itself, all it does is all its meant to do.

For whatever it is worth here is some info on my computer and the router and such.

My computer is a Dell Dimension 2350
Running Windows XP Home Edition
Version 2002 with service pack 3.
Intel(R)
Pentium(R) 4CPU 2.00GHz
1.99 GHz, 1.00GB of RAM

My computer's wireless internet reciever is a NETGEAR WG311v3 card. The router on my mother's computer is a BELKIN Wireless G Plus MIMO router. Younger brother who also disconnects uses a Linksys wireless G PCI Adapter, oddly my older brother with no connection issues uses the same linksys as my brother so I doubt the router is the problem.

Any help and advice is appreciated..if you need more information, please ask.

 

Forgot to mention, our internet provider is COMCAST. Sorry about that.