I received I-485 approval notice in May 2010 but haven't get green card yet. I am going back to China in 3 weeks. I was suggeted to go to local office to get a green card stamp on Passport. How to do it? Do I need make an appointment? Which office? I did biometrics in Hempstead (Long Island) USCIS office but I cannot find their phone number.Thanks for any help.