As per your neighborhood, the comps do not look good.
901 W 95th St is a 3 flat w/ 3brs each that had been for sale for 2 yrs. It is listed at $156k - clearly overpriced.
The highest priced CLOSED multiunit over the last year is:
8243 S Green - 2 flat - 9/26/11 - $66k.
With 3 of 4 of your units rented that is definitely a good thing. Value will be based on condition of units, location of building, and amount of rent you are collecting.