There is not address where you can get a copy of the visa that is in your passport except to contact the Embassy where she originally got her visa and see if they will be able to issue some documentation showing that she did have a valid visa stamp. Also, she would need to have a valid proof of her entry to the US, which is not the visa but the I-94. If she does not have that (it's a white card typically stapled or placed into the passport upon entry to the US), she can submit a request for a duplicate to USCIS. This can usually only be done if the entry was not too long ago and if she has secondary evidence that will help to locate it.
Answered on Nov 30th, 2011 at 4:21 PM