Well, I think you have to give it time. The whole pregnancy mantra of "nine months up and nine months down" applies here as well.
I wouldn't expect them to reach their "final" state until about as long as you were breastfeeding. Until then, maybe you can find a nice bra and do pectoral exercises and pray.
Personally, I don't care what they look like as long as I can stuff them into a pleasing shape under my clothes. But that's me.