You barely eat anything at all. You probably have reached your potential. Only thing left is to stop being so sedentary. Calisthenics, weights, sprinting ought to help improve your tone. Toss out your scale, though. You need to gain some muscle and up-regulate your metabolism, which has probably been slowed to a crawl, so if you choose to exercise more you'll feel more hungry and you will need to eat more.
Female, 5'3", 48, Starting weight: 163lbs. Current weight: 135.
Starting squat: 45lbs. Current squat: 145 x 4.