missing drivers after installing Win8.1 by Bootcamp

I was able to install Windows 8.1 64 bit in a separate partition using Bootcamp, but I can't get all the drivers needed to function properly.
I then extracted BootCamp5.1.5640.zip from Mac partition and try to install the drivers manually. setup.exe didn't work as it says it was not for the system. I then go to individual folders and install them separately. Still the missing drivers are still missing like the screen below.



So where can I get the proper drivers installed; I would need the wifi at least?

Thanks,

 

After trying most installers manually (from the Bootcamp update download), only Bluetooth USB Host Controller and FaceTime HD Camera (Built-in) left without proper driver. At least I'm connected to internet. I was able to see Mac partition before but it's not available now. How do I make it available so I can share files between the 2? (I can see Windows partition on Mac).

Thanks,