Autodial after a week

Is it possible to call the sale made customer again after a week automatically. I configure a second campaign where all customer with the status sale made will be called. The problem is, that every customer independent of the the last call time will be called.
Perhaps it could be work with filter. I could ask if the last_local_call_time < now - 7 days. Is this possible and when, how is the syntax of today.
Perhaps it could be work with filter. I could ask if the last_local_call_time < now - 7 days. Is this possible and when, how is the syntax of today.