Yes, you will want to enter both mortgages in the Your Home part of the return. You can classify the new home as your main home and your old home as your second home, the classification isn't terribly important as long as you do not have more than two homes.
For the old home that you converted to a rental, you will want to report 10 months worth of the interest and property taxes as a personal deduction in the Your Home section. The other two months should be rental expenses. You can select The interest amount I entered is different than what's on my 1098 box and attach a statement explaining that you are allocating two months of the interest for the period that the home was a rental.
