[Lizard]

1) Select the folder or project you want to report on and choose "Focus on [Your selected item]" from the View menu.
2) Choose "Context Mode" from the View menu.
3) Turn on the view bar
4) Set the following settings (left to right) for the view bar options:
(All Contexts) (Completed) (Completed) (Completed)

The first or second section will probably be labeled "Completed within the last week"