Weight Loss & Muscle Gain for Beginners

I reallllly want to lose some weight, but there's a few issues and concerns I have: A) My health SUCKS; I am literally in horrible condition health wise. I'm also very weak. Now let me say, I am not overweight- I just don't take care of my body. I weigh around 115-120, BUT, I'm short so I don't carry it well. B) The main problem areas are my stomach and lower back. I have the WORST muffin top. C) My boobs are great and I don't want to lose them.. now my butt, that's a different story- I have a fair amount of it, but it has no shape and I feel like it looks like an old lady's! **So here's what I want: I want a decent 6 pack (haha), I have to lose the muffin top, I want to shape the booty, and I have to gain some strength. Please help!!