Windows 7 - Switching from 2 monitors to a monitor and TV

Im using Windows 7 and I cant figure out how to do what I want to do. I normally use two dell monitors, but when I want to watch a show on my TV, from my computer, I extend it to my Sony TV and it uses the tv as one monitor and duplicates it on the 1 dell monitor.

id like to know if theres a shortcut, one click or "hotkey" i can setup to make this easier. especially since i keep getting confused which setting to pick to get this right. ideally id like to make it so when i press whatever hotkey, the tv duplicates the one monitor, and allows me to "extend my desktop" on to the other, or at worst case, just my tv becomes my desktop and my desktop is extended onto the 2 monitors.

anyone? thanks so much