I lost 42 lbs to gain most of it back and I can tell you as a women with a butt and chest, you keep it. Perhaps not all of it, but you do keep it. Your body stores fat in certain areas and that doesn't change. If you've always been busty, you will always be busty, but on a smaller scale. Just like a woman who is naturally pear shaped will always be a pear, your body will always want to store fat in certain areas.
Strength training is so wonderful for your body in so many ways. To firm up the body from head to toe, I recommend trying some DVDs. There are literally 1,000s on the market ranging from beginner to the most advanced with everything from ballet, strength, Cardio, yoga, ect. www.totalfitnessdvds.com
The above link is where I buy 99.9% of the DVDs in my collection.
Also look into SP's Fitness Generator. They will create strength workouts for you and all you need is 1-2 resistance bands and/or some dumbbells.
No need to worry, you'll love your body and will keep all the goodies!