You probably don't want any of the "state streets" in College Station. When I was in school (with small children also), I lived in the Oaks area in Bryan. I have also lived in the Southwood Valley area of College Station and I currently live near the hospital and Blinn College in Bryan. I still have one child at home. All three areas are family friendly and on/near a bus route to the university.
Bryan is a little more affordable than College Station, but I agree with Aggie98 - anything under about $700-800/month can be kind of sketchy.... more
Typically you'll have electricity, water (although some townhomes/condos will have this included), as well as an HOA fee which can range from $50-300 depending on the condo.
Without knowing exactly what townhome you're interested in, it will be hard to give you specifics of what these fees cover and how much they are.
With a townhome/condo project you can often have lower insurance rates since part of your HOA fees helps the Home Owner's Association pay for the complex. These multi-family complexes often take responsibility for the exterior meaning you're only responsible for maintenance and insurance to cover the "walls in".