If you're looking to add mass, why are you doing cardio? If you really want to add mass, you need to cut it out for now, you're going to gain more muscle with some fat that way, and you can always do cardio later once you like where you're at. As far as what to eat, theres way too much to list, get as many calories in as you can in 6-8 meals througout the day, but try to keep it somewhat clean if you don't want to add too much fat. Don't be too picky since youre just trying to add mass.