Congrats on your fantastic weight loss!!
I am forever top-heavy, partly due to broad shoulders which I cannot fix. But the two best ways I've found for keeping my apple/inverted triangle shape in check are 1) a Pilates DVD, for back and side toning and ab strength, and 2) Jillian Michaels 30 Day Shred DVD for serious stomach toning. Apart from that I jog, walk and bicycle for general fitness. Good luck!