Some people need more cardio than others. When trying to burn fat, the goal is to do as little cardio as possible to get the results you wish to achieve and that amount varies from person to person.
I would make an effort to do 4 days of cardio a week. After a few weeks, evaluate and if you think you need more, add another day, then look at it again until you reach that perfect level...not too little and NOT TOO MUCH (there is such a thing).
Also, eat your protein to keep the muscle mass. The more muscle mass you have, the more calories your body is burning when you are sitting on your ass. You don't want to burn off muscle on the treadmill...just the fat!