Well, to make the back more muscular exercises like pullups (or lat pulldowns) are effective. Deadlifts and rows are very effective. Ab work will also work the sides. Things like crunches and cable crunches
Another thing that really works the "core" (abdomen and back) is doing squats. They are specifically for the legs but are almost a full body lift.
Now about seeing the muscles you build, abs are made in the kitchen. That means to get rid of the fat, you need to of course do your cardio, but make sure your diet is in check. A 500 calorie a day deficit will take care of it for you in time, allowing you to lose approximately a pound a week.