Slow network connection

Here is my setup:

I have a Inspiron 530 desktop running XP Home SP2. To this I have a Netgear USB adapter WG111v2.

Also is a Latitude D600 also running XP Home SP2. This has a Dell 1450 wirelss mini pc card.

I have a Westell 327W which is a modem and wireless router in one.

I can connect both computers to the internet and both computers can see each other without a problem. My problem is that if I start to browse the internet on my Inspiron desktop the connection between the Inspiron desktop and the Latitude laptop become very slow. This is even after I stop browsing the internet until I restart both computers.

When I hover over the little connection icon in the taskbar on the latitude it will usually show fast speeds (between 18.0 and 54.0 Mbps), however the Inspiron desktop will show something very low like 1.0 or 2.0 Mbps.

Does anyone have any suggestions?