I just read this one otherwise i would have replied all in one shot. Let me tell you something, if you are out of country for school, ask your school for a week off and be here in the US for an Interview, I am sure you can cover that 1-week stuff later but rescheduling an interview may delay the process. I know it is easier said than done but 1 week off from school wouldn't hurt. It is just a suggestion. School would definitely understand and would allow you to go in for a week. If i was you, school stuff would be my secondary worry than my spouse passing her immigration Interview.