Hey Reddy139
I've fixed my problem thanks to "stevekesler" I've N5010 with Win 8 Pro installed too, use this steps to fix yours:
1- Download the driver "stevekesler" presented: www.dell.com/.../precision-m4500
2- After download Run the installer "As Administrator" select "Extract Without Installing ...>" and extract it to a new folder in any location.
3- Go to Device Manager by right clicking the Start Menu shortcut that appears when you move your mouse to the Down/Left corner on your screen, and press "Device Manager".
4- Now under "Network Adapters" right click your old WLAN driver, and choose the following in this order:
"Update driver software" > "Browse my computer for driver software" > "Let me pick from a list of device drivers on my computer" > Press "Have a Disk" > Click "Browse".
5- Now go to the folder that you've extracted the driver files in. and go to:
Drivers > Win7 > WL > Choose the file: "bcmwl6" and click "Open" > "OK" > "Next" > wait for the driver to install then press "Close", and that's it. you should have your speed back to normal, even without a computer restart.
Please tell me when you are done, Regards.