Thin apple shaped woman--desperately need fitness advice??

I'm a young woman and not looking to lose any more than 5 lbs at most--I'm a thin apple shape; I wear a size XS top and usually 0-00 pants. My problem is that I have a flat butt that I really want to enlarge, a belly (not a large one but definitely bigger than my bottom half!!) and... I lost about 50 lbs a few years ago and my breasts went from almost a 38DD down to a small 34B. Wreaked complete havoc on them--my breasts are small now and sag and I have a lot of extra skin. It's so embarrassing. I don't have the money for plastic surgery, so I'm hoping it might be possible to get rid of the sag/excess skin by building my pectoral muscles under what little breasts I have left?

My measurements are about 34-28-34. My torso is built like a column... I look great from the front or back, but turn me to the side and you see thin legs, a flat butt, and a barrel-like torso. So awkward-looking for a woman. So, my real concern is not my size, but my proportions!

My main goals are to build my butt up and get it to where it's larger than my stomach, as well as get it shapely; lose a few lbs to get rid of my small belly; and somehow make my breasts a lot bigger... Or at least to the point where they don't look so hideous. My goal is by December. If anyone has any advice for me, especially regarding building my butt/breasts, I would really, really appreciate it!! Thank you