What type of China Visa do I need for attending the conference in Beijing?

Dear Sir, I am holding Indonesia Passport with Service Passport type. Now, I am doctoral student in Hokkaido University. Next September 18-21, 2011, I will attend the conference in Beijing. For this reason, I have several questions: what type of visa do I require and is there any exemption for Indonesian citizens? If I need a Business Visa, is an invitation letter from the conference chairman sufficient? Or If I need a Tourism Visa, are the original and copy of Chinese Hotel Booking and Return Air Ticket required? How much fee of visa is required (in Japanese Yen)?