2.4 but no 5G on Windows Partion Side

Hello,

I have a 2010 Mac book air with bootcamp on it, (see below for full list of hardware and software specs) On Mac have snow leopard 10.6.6 and on windows side she have windows 7 home premium. I checked Mac side and can see both 2.4 and 5g signal fine. It's on on windows 7 side that only see 2.4 which is very very slow.

I also checked my ipad, iphone, PC computer, other Mac Computer, Android device and can see both 2.4 and 5g signal just fine.

Please do you know how I can fix this problem? I look forward to your answers

Hardware and Software Details:

2010 MacBook Air

OS 10.6.6. Snow Leopard

Bootcamp either 3.1 or 3.2

Windows 7 Home Premium / Service Pack 1

32 Bit Operating System

Wifi Router: Asus AC RTN66U

Wifi Extender: Netgear Black Hawk