GoPro's suck for still photography. Everyone I know has one and frequently they send me images asking my what's wrong with them. I try to be a little more polite, but the reality is they suck for photography, and especially in the water. Great for topside videography...
Take the advice in the posts above, but I suggest you have a budget in mind when you call, as well as a top figure that you won't pass. This hobby can cost a ton of money, so it's important to understand your budget and balance that against your expectations. The corollary of this is that a good camera won't take good pictures in the hands of a bad photographer... They'll just be more pixels. I know people with $20000.00 systems that can't seem to get both ends of fish in the frame.
If you want to take "serious" photos, then you need to spend a few bucks on gear. I would think at least $3-4000.00 with all of the bells and whistles... that should get a decent p&s camera, a housing, a strobe and some attachments. That should get you a decent starter system. If your budget is $500, then set your standards accordingly, and have fun with it.
Photography is a bit like sex. As long as you think you're good at it, and you're having fun, who really cares what anyone else thinks! ;-)