You need to work your whole body when you do weight training. All of it, even the legs and back.
For your cardio, I'd suggest one or two workouts a week of
interval training to kick the intensity up a notch.
It's not possible to spot reduce, you'll need to lose all over bodyfat to lose it from the abs and sides. For this you need to create a
caloric deficit. You should track everything you eat for a few days, and then try cutting out about 250 calories to start with. You can adjust based on your results. Make sure you're getting enough protein; try for about a 40/40/20 carb protein fat ratio to start off and adjust later.