I didn't have time to read all the replies to this so I'm sorry if I duplicate what others have said.....

What you want is EXACTLY what I want.....lose the belly and tone and lift the butt. Well, I read you said you are doing sit-ups? I don't knwo if you mean sit ups, or crunches. If it is indeed "sit-ups", ALL professional and serious exercisers and trainers say they are worthless. So make sure what you are doing is crunches. So target the sides lay on your side, knees raised and "crunch" to the side. Make sure to squeze your abdominals in. If you do the crunches w/o holding your ab's in the muscle you build will be sticking out rather far. That's the best way I can think to describe it. The muscles will build that way. if you want them flat and hard, hold them in.

Squats and lunghes (spelling ?) are great for the butt. I personally hate them! They are hard and that's why they work! Another that's great is on all fours, start with one leg raised and bent 90 degrees, and lift. Another way, do all the above and then turn the leg out (so it's parallel with the floor) and lift. Even harder is to lower the upper part of your body to the floor so you are resting on your forearms. Even better for the butt!

One more word.....not to discourage you.....but this things will not cause you to lose WEIGHT in those areas. You can not spot reduce.....but it's great to be doing what you are because once you get the weight off you will have beautiful muscles that you will finally be able to see.

Keep it up. You seem really focused and that's what it takes! BEST of luck!!!