I'm an inexperienced singer. I love singing and have a decent "ear" for music, but my voice is very weak. This means that my range of full (chest) voice finishes very, very low. On the other hand, I can hit quite high notes (I was classified as soprano). The most problematic notes are notes "between" - I'm very quiet when I sing them, and it doesn't sound good at all.
My question is: How to improve this in-between range?