"The situation is like this. My wife's elder sister is U.S. citizen and living in the USA for the last 09 years wit her husband , who is a doctor and well settled.

My wife, her parents, and the younger bother were sponsored in year 2002-2003. by the elder U.S. citizen sister. At that that time my wife was 19 years & not married. Recently, she has got married with me, on August 15, 2007.

In this December 2007, My wife, her patents and younger brother have received their .
(Form I-864), and the interview + medial call letters from the US embassy in Pakistan, given time May 2008.

Question:
What is law and policy as per in this situation, is she still eligible for the immigration?
Can she sponsor us as well after getting her immigration? How long it will take?
One more point, its my second marriage, because my first wife had passed away 04 months back due to Cancer. I am 29 years old and working in bank as Financial Consultant Officer. My wife has done her MBA. I also have a baby boy, whose age is just 15 months old, and he is living with us. Is there any hurdle for him to immigrate to USA ?
Please email and guide me soon.

Kind regards,
MC