There are plenty of exercises you can try to tone your core. The LeikeFitness Height Adjustable Ab Trainer can lend you a helping hand. It has 5 levels of resistance and can handle users up to 220lbs. This ab cruncher has sweat-resistant pads. It has a LCD display to show how much progress you are making.
The LeikeFitness Ab Trainer works your arms, legs, and glutes too. Not too expensive either.