Losing Weight, Its Hard..

I am a Big Em-effer I weighed 352lbs I have lost 52lbs just working out and eating healthy when I mean Healthy, I mean Healthy!! I used to eat all Kinds of Crap!! I used to do Food Challenges like Big ass burritos from El Albajeno, Big giant burgers from Outlaws!!, Giant pizzas. well you get my drift!! and  I was too damn fat!! so I decided to go on a diet so I started eating for Breakfast I had a Light Yoplait Yogurt and Protein Shake and for lunch a salads from Tacone (in the mall by My job) Grilled Chicken, Lettuce, Shredded carrots and a cup of water  and then after work 'd g to the Gym did 20 mins of cardio and then lifted weights.. My dinner was a otein shake after my workout  Plus I was drinking water all day but in the first three months I lost 40bs then I lost 12lbs And cant seem to go below 300lbs My goal is to be 250-260lbs with muscle. I have not taken any Diet pills or anything... YET  what do you think? or recommend??