Women: Developing Strong Chest/Pectoral Muscles

rosestring

So, I want firmer, perkier breasts. Okay, now that that's out of the way...

I don't have dumbbells, except at the gym. How important are they in doing upper body/chest exercises? I'm only able to go to the gym a few times a week. What other exercises can I do (for example, push ups?) that can really help develop those muscles?

I realize my breasts won't actually get bigger, but someone told me theirs went up a cup size after really defining their chest muscles. I guess the muscles kinda helped to push out the breasts. Could this be possible?