some protein shakes would be a nice supplement, and for right now, probably the only supplement i'd recommend.

if you wanna firm up and put on a few lbs of lean muscle while losing the tire, you're gonna need to work on both the diet and your exercise regiment

for the diet you can start cutting back on processed carbs and sugars while upping your protein intake 1-1.5g/lb should be plenty for now.

as for cardio, you can do sprints, long distance jogs, goto a stadium and run the bleachers, etc. just get creative.

for the workouts, i'd recommend doing as many compound movements as possible. bench/incline are good, pullups and some type of squats would be great. you'll make good progress pretty quickly since you're just getting back into it after a long layoff.

lots of great peeps here that can help answer any questions you have.