Could you please help me to get a visa to Hong Kong , and how long it will take, and what else required for that?

I would like to attend a conference in Hon Kong 26-29/8/2013 , I got an invitation from the organizer , Libyan passport, my scientfic paper to participate in th conference, my Id as a teaching doctor in the Tripoli University,
Dr. Abdalla M. Al-kelsh
thank you