I can't give specific suggestions, but I will say to look at the tags/labels. If you go to a sports store (like Dick's Sporting Goods) and look at the bras there, the tags plainly identify how supportive the bras are intended to be. The ones that look the most comfortable are usually the ones that are for "light" exercise (walking, yoga, etc). Then there is "moderate support" which is more for biking or weight lifting or whatever. I need the strong support ones that specifically say for "running", because otherwise, it is not enough support.
I'd guess that a bouncy aerobics class would require something similar to what I use for running. I'm a C/D cup (depending on if I have gained or lost the pesky 5-7 lbs that come and go) and if I wear anything less supportive than I should, my chest hurts (not my girls, but the chest wall).