I suggested that yuo plan a short vist to the Victoria Peak in Central. Firstly, you could take the Airport Express to arrive at MTR station of Hong Kong in 30 minutes. Then, you could walk to Central or take a taxi there. At Central, you could find a bus terminus where the bus No.15 could drive you to the peak directly. Have a short visit there and then ruturn to the airport on the same way~ Please note that because of the H1N1, the security check for international flight may be longer. You have to master the time properly~