在等绿卡期间，换工作及回国（请各位老师帮忙解答）

Background: My green card is in process (my parents are citizens).
I had my finger print done in Jan 2015 and received my EAC(employment authorization card) in Feb 2015. 

Question #1: How long do I need to wait to get my green card?

Question #2: For my new job I will use my EAC card (don't need H1B anymore), how can I travel to China for work and reentry back to U.S? Advance Parole? Will Advance Parole delay my green card process time?

Question #3: For the new job I am moving to another state, so I have to change my address for the letters to come. Will moving to a different state delay my green card process? 

Thanks in advance for the help!