In my area, it's further split up. There was preschool, of course. Then Kindergarten at age 5. Primary school was K-2, elementary was 3-5, middle 6-8, and high school 9-12.
As far as college or university, think of it this way: A college focuses on basic education in a few fields. A university would go into more depth over a wider range. Most universities contain a number of colleges, but if you go to a smaller school, it may be a single college on its own.
That's the technical perspective. In general speach, no one goes "to university." In casual speech, you always go "to college" -- but if your college was part of a university, when someone asks "Where did you go to college?" you'll tell them which university.
