Visa for Hong Kong.

Myself and my husband are planning to visit our daughter and son-in-law in Hong Kong for 20 days. We have already got our tickets made . However on arrival visa for Indians is only 14 days. We do plan to travel to Macau and on arrival we can get another 14 days extension of the visa. Is it ok to carry a return ticket showing a date later than 14 days? or should we apply for a visa. We dont intend to stay for more than 20 days. If we apply for a tourist visa, how many days will it take? Please advise.