There is another option you may want to look into...
If you don't mind leaving the desktop on while you are on your laptop, what you can do is install a second NIC in the desktop, have the first NIC wired into the hardwire router, install the wireless router into the second NIC, and bridge the two connections in Network settings under XP on the desktop...
What this accomplishes is that the wireless router will take the settings from the desktop and act as a gateway for the wireless.
You should be able to have the two computers on the same network...
You can follow this link...
http://www.microsoft.com/windowsxp/e.../02april22.asp
Hope this is a valid solution for your problem...
Ed