I guess once you have your garrison established, that button appears. But it's right over my main bar, which I need to see the procs (on my paladin). It's not the "extra action button", BarTender shows it much higher.
I do have MoveAnything, but I don't know what's called so I can move it. Anyone care to help? (strangely enough didn't have that problem on my priest...)
Proteen's suggestion should work, but also, when the moveanything frame is up, there's a little checkbox in the top left with the text "FS" next to it. This brings up Blizzard's frame stack display (alternatively you can just type the command /framestack), which will show you the name of all the frames you are mousing over. There will be a hierarchy list of frames, but the one you are looking for (or at least, the ones you are not looking for) is usually fairly obvious. Then you simply type /move FrameName and it will bring up the moveanything move UI.