how long it takes the recive welcom notice in the mail after email


New Member
I have recieved an email from Texas Service Center, which says "On April 17, 2009, we mailed you a notice that we had registered this customer's new permanent resident status". I assume this means my green cars has been approved. How long does it take to receive this notice in the mail, and pyhsical card after that? I am going out of country on may 5th. i dont think i will get the card before that. the visa stamp on my passport is expired already. do i need to get a Visa to be able to come back?