I'm currently using a simple Pentax Option WG-2 which takes perfectly decent shots but I'm thinking of upscaling to something closer to the professional end of things. I'm just an amateur photographer but would like to further my skills and am considering taking some classes being offered at a local college. What would you recommend for someone in this situation?
I'm not sure I completely understand what you are asking about. Are you asking for advice on what kind of camera/lens/flash/waterproof housing to get? ...or what kind of classes to take? ...or something else?
There are no rules for good photographs, there are only good photographs. -Ansel Adams
Getting better image quality underwater means two things: bigger sensor and adding flash. You can get the bigger sensor for a (semi) reasonable price by getting one of the new Sony NEX compact cameras and a reasonably priced hard plastic underwater housing to go with it. But if you want a housing that allows you to use underwater flash units then the price goes WAY up.
Another option is to put a standard dSLR and flash into an Ewa Marine or Aquapac underwater bag. But you can't go as deep and you have to be more careful about damage. Give it a good rub on the coral reef and your camera might be flooded.