Wifi issues persist in 10.10.2

I'm running a MacBook Air (August 2013) and everything is up to date. I have a full wifi connection in my bedroom. I have ZERO problems with my iPhone, iPad, Roku and Apple TV in the same room, however my MacBook Air is extremely slow on wifi or just flat out not work even though in the status bar it is full reception.

It is very frustrating that it's not working. I do have an external monitor hooked up it seems as though that may be an issue when I disconnect it seems to work fine but I can't be 100% sure.

Anyone have any solution to this or an idea? I would like to have my external monitor hooked up to my Mac. This was never an issue with Mavericks. I regret installing Yosemite.