Hi,
I am working on OPT since Oct 2012. As per today my federal tax details are as below :
FEDERAL W/H ( CURRENT ($) =485.57 & YTD ($) = 7885.53 )

So if I am filling tax return in 2014 as single then how much federal tax refund should I expect? I am married and I am planning to bring my wife here by December so does that matter while filling? If yes, then in that case how much benefit I should expect?
I am from India and I did my MS here.

Thank you.