Is that okay OR I need to get a new birth cetificate for my wife ?
Answer: Get two affidavits from your wife's parents, elder siblings, wife's relatives who are old enough to know that she was born to her parents. I have the same case as your wife and my attorney recommended getting affidavits which i got from my mother, father and eldest brother (2 required but i got 3)!
Also, what tax related documents do I take ? Do I need to take any document from the local IRS office here in USA ?
* Photocopies of your last 3 years tax returns for fed, stat and city if any.
* W-2 for same period
* Request transcript from INS for same period by calling 800-829-1040. You will get this 3 year trancript within 10-12 days of placing the order.
Disclaimer: I am not a lawyer. My replies are based on knowledge gained on immigration sites & my studies on US immigration. It is always good to consult an immigration attorney such as Rajiv Khanna. If you have specific questions for me, please PM me.