Does the desktop use a USB dongle or a PCI card for it's wireless. If it is a PCI card you can get stronger antennas for them, at least the older ones I had you could. They made a weak to non existent signal in my house actually work at 54MBPS.

There are also other alternatives to wireless, one such system is powerline ethernet but it would be cheaper to just run a wireless repeater.

Jason
M80 v2
VP160 v3
QS8 v2
PB13 Ultra
Denon 3808
Samsung 85" Q70