Re: what to do!
Have you thought about highlights? They always brighten up your hair color and look beautiful. My advice is to start off with natural ones a few shades lighter than your hair color. If you go too light at first, it may not look natural and instead may look streaky. The first time I ever got highlights in my medium brown hair, I got caramel colored ones. Next time I got blonde ones and continued to get the blonde. Both looked great and they would gradually lighten my hair as I went each time. I recommend foil highlights... I wasn't happy with the cap kind and never got them again after the one time. Also, the at-home kits often don't come out the right color, so it's worth the money at a salon (especially if you want blonde). Just go for lots of thin highlights all over so they blend in nicely.
For your style, you can always consider layers. Just tell the hairstylist (if you decide to try that one out) that you are looking for more volume. Layers are great... you can make your hair look thicker or thinner depending on how you fix it. My hair is too thick and heavy, so they cut a lot of the bulk out of my hair, but they keep it bouncy with volume. Try looking at some pictures in hairstyle magazines that you can take in with you!