Plateau.. need some tips

Jspkt2002

I have lost 13 lbs since jan 28 and decreased my body fat from 19.7 to 18.5. I am currently 204 but I have been that weight for a couple of weeks. I normally eat about 1500 cals a day work out about 6 days a week for about an hour normally. I can notice the change in my arms and legs but not my chest and stomach. I do an abs class for 10 min 5 days a week as well. I would appreciate any tips or different workouts I can try to tone up and improve my physique.