weights help me lose 50 pounds in 3 months

Hi,

i am a married 41 year old mother of three who works fulltime as a director.  after my last child was born, i was a wreck.  looking at my fourth decade and having just lost my mother to ALS, i was exhausted, overweight and discouraged.  resolving to do something about it, i hired a very pricey trainer a few blocks/5 minute walk from my office and started down a path of transformation.  my trainer, from my first consultation, recognized what i had to offer - under my 38% body fat was lots of muscle due to body type and sports.  with three, 30 minute intense workouts a week and a high protein, low carb, ~1600 calorie/day diet, the fat literally melted off.  what a transformation!! everyone thinks i am a 33 year old and they can't believe i have three kids (i have always looked younger than my age).

i added my own workouts and in three months i went from a size 16 to a 10 and a few months later i was fitting 4s and smalls!  i have settled at a 6 and continue to use weights as my primary means of working out.  i prefer weight training for its bang for buck and am always looking for new workouts, which is why i joined this forum. 

my challenge is keeping my body fat down and right now i would like to get much leaner but i think i have plateaued.  currently i do 6 workouts a week, alternating upper body/abs and lower body/back with occasional soccer games, run and plyometrics. does anyone have any advice on how to do this?  i would like to lose about 7% body fat. i am around 24% now and would like to get down to under 20%.

Thanks

deb