Mr.frank, it is not wise to state that you will go to Tibet, you can get a tourist visa to China first, after arriving in China, contact a travel agency which can get a Tibet Entry Permit for you, the visa fee varies according to the entry numbers, it is 40 Australian dollars for single entry visa, Generally speaking, the single entry tourist visa valid for 3 months and permits 30 days stay after entry, you can have a try to apply for a single entry tourist visa permits 60 days stay in China.