Plane ride from Singapore to Brisbane 7 1/2 hours and the cab from Brisbane airport to Gold Coast is about A$180 for 4 even though its a maxi cab 4 or 7 same price. We booked a 7 seater Kia Carnival for about A$120 per day for 6 days.
Meriton Service Apartments 30th floor at Broadbeach for A$366 for 3 days 2 nights. Has kitchen, master bedroom another bedroom and a study room as well as living room. Suitable for 2 couple and some kids. Good deal. Melbourne was a 3 room apartment for our 3 couples at A$200 per day. Tram is directly outisde and its a few stops to city centre.