As a guy said above there is no such thing as spot reduction. So you can't just lose the fat on the belly, it's impossible. To the guy said crunches and so on, this will sort of work, eventually he'll have rock hard abs, but that layer of fat will not remove it, so they won't be seen.
For your workout, do some full body compound excersises - Squats are probably the best. Things like barbell roll outs, deadlifts, dips, press ups, chins ups, you get the idea. You can do a bit of ab work, but they won't make much difference at first.
Do HITT running or HITT swimming are probably the best things you can do. If you do some swimming after your workout you'll just die, it's a killer trying to swim for long after a workout
Don't just get on the treadmill or whatever and run for a long period of time, better off doing a shorter one but getting the intensity up and down (read what HITT is)
Weightlifting is better than cardio for it. So a better weightlifting routine would be more beneficial.
Start eating right too, your calorie intake doesn't matter as much, maybe cut it by 300-500 calories. Just make sure it's good food your eating and not junk.
Remember your rest days are as important as your workout days.