Like the above says, you cannot spot reduce, you lose weight you will lose it all over. It may at first vanish from one area early on if you lose it too fast (like say your face or chest) but then things even out over a few months and your back to where you left off.
Maybe you could try pilataes or core exercises? they work on your transverse abs which is the muscle you use to hold your belly in. Its a muscle you can very easily work to pout outwards when you do sit ups (many people 'push' their stomach outwards when doing any ab work and train their muscles to pout rather then pull inwards) so make sure you at least begin your training with someone to watch out for you. You can then train your muscles so that when you hold in, you hold in that little bit more then normally
Either that or its Spanx or the knife....
