If you want the current week, then you may be out of luck. If you want something a little looser like within 7 days, then that should be easy enough.
Place a constraint on a hidden question. When survey is first created, create a date calculation (e.g., ${form_start_7}) to be something like today+7 days. Then, have a second hidden date question (e.g, ${date_today}) with calculationMode=always and set the default to today() so each time the survey is opened it is today's date. Then, compare the two dates in the constraint question, ensuring ${date_today} is <= ${form_start_7}
Not something I've tried to do before, but should work.