Is this a good workout routine?

I'm 5' 1, 100 pounds and I already do a lot of cardio. I have a flat stomach but I'm wanting abs. I can't pinch fat on my stomach except for a little bit at the bottom. I also want toned arms. I'm lifting 3 pound weights (150 repetitions) and doing 200 sit ups 5 days a week along with my usual cardio and increased protein intake. Will this work?