[MooBerries]

JIf you buy a noogleberry you will need at least an xxl cup by looking at you be warned Lucy trys to sell smaller sizes than you actually need sometimes I think so you grow out of them quick but a slightly wider cup will help fill out the breasts around more.
As well as exercise as Beckie said I remember I did insanity work out and although its not even that chest focused it did make my breasts a little smaller but much much perkier so maybe something like that will help you.
Another easy way to make breasts appear rounder as you have big areolas but small nipples( this can be natural but also common with hypoplasia) you can shape your nipples which does reduce the areolas slightly and more erect nipples make breasts instantly look firmer I like to use the niplette but supple nips look better as they are softer and have size options.
Some people use cold water for firming I'm not sure quite how maybe worth a look.
Also trying a natural progesterone cream or bo could work well to help if the problems hypoplasia.
I think you will be able to get good results it will take time.
I think the problem isn't just sagging and that there is something else have they always looked like this shape have you lost or gained a lot of weight or anything that might have effected them and was it during since their growth.

No They have always been shaped that way