That's OK if you can't go to the gym - here are some things to explore:
1- Is your diet reflecting the weight loss - if you are "physically smaller" you may need to cut down on calories - even if the plan worked till now. consider dropping 1 carbohydrate serving, some of the healthy fat servings (I hope you are eating) - ad one fruit snack serving to balance out those calories lost
2- Buy 3 sets of hand weight - maybe 3 , 5, 8 pounds. Invest in some weight training DVDs or go online for some basic weight training programs. Adding on muscle mass will help to rev up your metabolism and help you to nudge the weight
3- Within your walking hour - add some hills and valleys and pick up the pace - you do need to raise your heart rate to burn calories, especially when your body is accustomed to the current walking program.