The lower body is typically the hardest place to lose weight. Make sure none of the foods, dressings or soups you're eating contain MSG in any form (including most restaurant & fast foods), as this will hinder your weight loss. http://www.naturodoc.com/library/nutrition/MSG.htm
You may also have to ramp up the burn a little, if you're body's now use to the walking. Bellydancing worked for me to get the last few pounds off and tone up my butt and thighs. Unfortunately, this is where the "if it doesnt hurt, it doesnt work" mantra comes in. You need to break a good sweat and really feel the burn after a workout. That encourages bloodflow to the area to repair the muscle and clean out the fat. Sweating will also help increase your metabolism and your desire for more water - the more you drink, the more you'll lose. Dont give up, it takes a long time. I gained 40lbs while I was on chemotherapy for cancer, and at about a pound a week, it took me almost a year to lose the weight and another year to see the tone I use to have. Most of my major sweating comes from yardwork - mow the lawn, plant a new bed, add a concrete/stone path someplace, etc. just get really drippy. Last Saturday I laid a new stone path - checked my weight that morn at 122.6 - drank close to a gallon of Gatorade (was a terribly hot day) & toweled off regularly. By that evening my weight was at 121.2 (and that includes the over 8 pounds in liquid I consumed that day.) So try not to get discouraged, dont think of it as a diet, but as a lifestyle change. The weight wont truly stay off unless you eat healthy at every meal (with the rare exceptions). For myself and my family, all that took was eliminating all processed foods - I cook almost everything from scratch (cheaper than mixes, with no addatives). I use items like real butter and cream over vegetable oils and cream substitutes, (Counting calories never really worked for me anyway), but I keep my portions small - typically at the serving size or less. We grow a lot of our own fruits and vegetables, my girls (8&9) help out with that as well and love it, so we have something from the garden at most every meal. And tending the garden gives me another good reason to sweat. I hope my story gives you some inspiration and keeps you from being discouraged. If you'd like any tips or have questions, feel free to let me know. Good luck :}