In order to lose 1 lb per week, you need to cut your caloric intake by 500 calories a day as 3500 calories make up one pound of body fat. Or you can burn an aditional 500 calories a day with your cardio workout. The other option is to reduce your caloric intake by 250 calories/day and burn 250 calories during a workout. I am also 4' 11" and found by staying in my target fat burning heart range, I can burn about 350 calories in a 45 minute cardio workout. Sometimes I track the calories I burn by wearing a Polar F11 heart monitor. Low Impact Circuit, Body Max 2 and Drill Max are all great workouts. You can view footage of the video on Cathe's website. Also, try not to snack after you have dinner. You don't want to undo all your hard work by replacing the calories you worked so hard to burn off.
Good Luck and let us know how you do.
Lina