Don't believe Windows Update! It'll only list that stuff that's been submitted to it (and approved by them). The "Update driver" thingie goes to Windows Update.
Here's the Realtek download site:
Realtek
Here's the nVidia download site:
Drivers - Download NVIDIA Drivers
and here's the NetGear download site:
Answer (this version does have 64 bit support)
IMO it's best to download drivers from the manufacturer of the device - rather than the manufacturer of the device that it's placed in (such as the system or mobo manufacturer). Sometimes there's no other option tho', so it's a balancing game.