I am the sole breadwinner for my household, which consists of my girlfriend and her 2 kids (not mine). 1 child is in school, and the other is 2 yrs. old. Mom stays home and takes care of the 2 year old, so she has no income. What filing status can I use, and can I claim "mom" as a dependent? How can I maximize my refund? Any childcare expenses that I can deduct?