Put the new litter box behind the TV in exactly the same spot you found the poop. She's already in the habit of using that spot.
Surround the box with slightly crumpled newspaper (they don't much like that) so she won't be as tempted to go just outside the box. And if she does anyway, it'll be easy to clean up. She'll most likely prefer using the box.
Putting a little of her poop or pee in the box is a very good idea, but not too much. They don't like it when it gets too dirty. (Some are really finicky about this.) I second patiodog's advice about scooping every day.