Messing with monitors for Steam Big Picture

Hey people,

I hope this counts as hacking. My PC is within a stones throw of the family media center. Today I finally put 2 and 2 together and bought a 10m HDMI cable that goes from my 650 Ti > Anthem MXR300 audio/visual thing (so that the better speakers can be used) > TV screen. Gaming is better on the PC :D but racing games need analog input and trying out big picture is interesting.

Anyway, I need a way to switch between the two set ups running from the single machine. (Win + P) works (although it treats the TV as my main display even though the settings say otherwise). How can I make a macro/script/batch file/(use) 3rd party app that will switch both the AUDIO and VIDEO. If I could press a button and have the unneeded display turn off/needed on and have the default audio device switch I would be grateful. 

PS: I can just unplug the HDMI and change the settings every-time but hackers 'aint go no time for that! :D