A picture would greatly aid in the helpfulness of my advice but have you considered knocking down some of the doorways and opening up the space? If that's even possible, once you do that, you might be able to extend your kitchen out a little farther and fit in an island with bar seating to accommodate your family of 4. And I am a total believer in natural light and absolutely hate removing it, but if you need to get rid of a window in order to make your space work, then hey, do it, and install pot lights to replace some of the light you lost. Good luck and happy renovating (:

Are you planning on replacing the cabinets, countertops and appliances?