I have 32 bit Win 7 but lets pretend it is the same.(I just installed it on my wife's 64 bit laptop, we are good)
Step 1) print a config report so you know it's IP address.
Step 2) download this driver
As you run the installer, it will ask you local or networked, oddly it is local
It will ask you if it is a new or existing port try existing and look for the IP Address you got from Config
If not try new and use a Standard TCP/IP Port and enter the IP address
Once you get to a list of Printers, push the Have Disk Button and then the Browse button. For me this put me in the correct directory but it is named very obviously C:\xerox\p7760_PS_64_Driver
Choose the only visible file and click OK and you will get a list of 3 printers, the GX is on that list. Then just agree to everything until you are done. Once done In Configuration in Printer properties you can configure your options.
I tried to remain child-like, all I acheived was childish.