Hi Smspearson, and welcome to Spark People!! Congratulations on your weight loss. It sounds to me as if your body has adjusted to what you are doing. Try adding more time to your work out or changing your work out all together. Check out the free workout videos on here. They have them for every exercise level and they even have chair exercises. You can find them under the orange tab at the top of the page titled "Articles & Videos."
I wish you much success!!!