turning40withMickey, thank you so much. This helps alot!
From your pic, I'm estimating that the Pop window is about 44" wide, as I'm assuming that you centered the Minnie bag in the center of the window.
And I'm thinking that the length of the window is about 60". I'm not too concerned with the height of the ledge of the window, but my guess it's between 2-3 feet above the floor.
And BTW, your window is very nicely decorated! How did you attach the mickey heads to the window? It doesn't look like you used tape, or if you did, it was not noticeable at all.