suggestions for our holiday in Hong Kong.

Both of them are acceptable. Once upon arrival at the airport, there are banks, ATMS, currency exchange sites, you can withdraw or exchange some HK dollars according to your budget. Just comparing the rate provided by different counters, you will get a reasonable rate.

If taking a taxi from the airport, it may cost you HKD240 to the hotel. Well, there is an economical way: Take the shuttle bus No. A21 to Hung Hom Station, which is very near to your hotel. Then walk a few mins to reach. The bus fare is HKD33, and the duration is about 75 mins.

From your hotel, you can walk to Hung Hom Station to take the East Rail Line to Sha Tin Station. Then walk about 600 yards, you will arrive at the Ten thousand Buddha monastery. The fare is HKD5.7 and the duration is about 25 mins.

Your time is tight, you it is possible for you to visit the giant Buddha in the same day. Walk to Sha Tin Central Bus Terminus, you can take the E42 to Tung Chung Crescent. Then walk to Ngoing Ping cable car terminal, where you can take the cable car to the Buddha.

If you just stay for several days, and you will have the round trip to the airport, I suggest you buy a travel pass including one or two airport express rides, and three days unlimited MTR Ride.

Thank you for your answers Gary. We will stay in HK two and half days. How much is the travel card and where can I buy it? Thank you

Well, as I mentioned, you are suggested to buy Airport Express Travel Pass.
There are two types of this card. With HK$50 refundable deposit, the difference is single Airport Express costs 220 HKD and two Airport Express costs 300 HKD.

You can buy it at all Customer Service Centres of the Airport Express stations. :-)