If you would like Get It Done to put a task in your Today folder (or another Focus Area) every week or so, you just have to set the task to be repeating:
- Open a task
- Tap on Repeat
- Set your repeat pattern (note: there is a "only if last task was completed" checkbox. This can be handy for tasks that you care about when the last one was completed)
See also how to schedule a task to appear in my Today folder.