Office hours are not tutoring sessions; to get the most out of them you should prepare your questions in advance, and you should be able to to show me your attempts to solve the problems you want to discuss.
My office is Keller 401. My office hours for Fall 2013 are by appointment only. I am in my office most days, so if you want an appointment you can just stop by. Other than that, the best way to make an appointment is to contact me by email.