Well, I always struggled to fill a 34B so I don't have much experience in this area but someone posted on my question about exercise attire and suggested the shock absorber bra from www.figleaves.com. She said she's a 32G.

Someone also suggested trying www.lessbounce.com and a lady with 36Ds suggested these by Champion: http://www.amazon.com/gp/product/B0038A2A52/ref=ox_sc_act_title_1?ie=UTF8&m=A3JMZ4EL52GCAP. - they have great support and no underwire.

Hope you find something