Yes, you need a visa to Hongkong, the basic requirements are
1. Original passport with validity more than six months and minimum 2 blank visa pages;

2. Photocopy of the first 2 pages (personal information) of the passport and the recent Chinese visa page if there is any;

3. One fully completed visa application form in Chinese or English, attached with one of the applicant's recent color photograph (30mm X 40mm)

Please note: You should first contact a qualified travel agency of China and settled down all the details of the tour. And then the tourist agency may arrange a visa notice form for a travel group (more than 5 people) and a group-visa for you. At present, individual tourists are not accepted.

Besides, you are recommended to apply for Hong Kong visa 6 weeks in advance and may apply directly from Hong Kong Immigration Department.