Trying to los weight and make my muscles show under the big layer of fat..could anyone help me?

i started weight lifting and starving.so i lost weight but i got muscles.then i got my diet straight and after a year of working out i got muscles under fat.how could i lose weight?im doing swimming now and i lift weight twice a week maybe 3 sometimes.but im also thinkin about p90x lean.im 250 lbs 6'1 16 years.so swimming and p90x or just swimming or swimming and lifting weights?