Working but very slow wireless network

I was wondering if anyone could help me understand why my wireless network
is so slow. I have a Belkin 54g PCI card in my desktop and a 54g enabled
laptop. I have set up an ad-hoc network between them and set up internet
connection sharing so that the laptop can use the ADSL line connected to the
desktop. That all works just fine. But the connection speed is not 54Mbps as
I had hoped, but mostly 1Mbps. So not 5 times faster than 802.11b but rather
11 times slower. This applies even when the two machines are in the same
room sat next to each other on my desk.

At this connection speed file sharing is almost impossible, or at least
pointless. I can copy the files between the machines using a CD faster than
I can using the network. It takes ages just to get a directory listing of a
shared directory.

Could interference with other equipment be a problem? Is there anything I
can do about that? What is the significance of the channel number and can
changing it help? If so what values can it have?

Any help greatly appreciated.

Cheers,

Neil Jeffrey.