to install drivers that didn't come with an installer:
Go to Start and right-click on Computers and select Manage. This will bring the Computer Management window, now on the left sidebar select Device Manager.
Now, select the device who’s driver you want to update. The WiFi device is probably under "network adapters." Finally, click Update Driver Software. Select "find drivers manually" and browse for the folder containing the driver files you downloaded.
Fujitsu doesn't have windows 7 64-bit drivers for all models unfortunately. You can try the Xi 3670 drivers, I think that model has the same WiFi device, and it's for win7 64-bit. Or indeed look in the Atheros website for some drivers.