K.,
We were preschool parents for 9 years, and we always had very thorough, indepth, warm conferences, no matter the teacher...and some teachers were much warmer overall than others. Our preschool was not an academic one, but a developmental one, and we would be shown a list of behaviors, social skills, etc., and there would be personal notes written next to each item on the list. We always felt that the teachers had an excellent handle on our children, as their words and emotions would reflect that.
That being said, perhaps you had your conference on the teacher's "bad day." That's not an excuse, but perhaps the teacher wasn't having a good day. Or, perhaps the school does not put a premium on the parent/teacher conferences and does not train the teachers regarding what to discuss, and how to discuss it.
The advice from other posters is good...go in with pointed questions. I just wouldn't wait for your next conference, as this is bothering you, and as you have so little contact with the teacher. I would ask to meet with the teacher(s) sooner. If this is an issue at either end (though it shouldn't be at the school end), then perhaps at least have a telephone conference to have your questions answered.
At our preschool, we had to drop off and pick up the kids at the classroom door, from the teacher(s), and often we would receive stories and antecdotes at that time. The personal contact is important.
Good luck. If you are not feeling satisfied after making other attempts to get info, then perhaps you do need to look at other preschools. No place is perfect, but our preschool was close :), and I hated leaving it, even after 9 years!