Australian family with 2 older kids looking for a helper

We are an Australian family with two kids aged 10 and 14, looking for someone to replace our helper who's retiring after many years with us. It's a relaxed household and we require someone who can be flexible around our work schedules. We are looking for someone who's well organised, happy to work independently and can handle the housekeeping budget. The main duties apart from looking after the house is to supervise the kids in the afternoons and evenings if necessary. We are also looking for someone who's an excellent cook. We are living in Happy Valley.