Application from China

Dear Madam/Sir

I am Hungarian citizen, staying in China with a VISA valid for 2 times 90 days. I would like to apply for a 12 months VISA with multiple entries and exits. Is it possible to do it from here? If yes, at which authory shall I submit my application? I am staying in Chengdu. Where do I find the closest of this authority. What are the documents I have to submit with my passport and application form additionally?

Thank You!

Bence Takcs