Women are usually turned off by the idea of becoming too muscular, so they shy away from lifting weights. But in reality, muscle is needed to burn fat. The stronger you are, the faster burn the calories.
Grab a 10 pound kettle-bell and swing it like a pendulum between your legs for cardio and strength training, or do dead-lifts with a body bar for lean arms.
Studies show that those who incorporate weight training into their workout routine burn more calories while away from the gym than those who rely on a strictly cardio based fitness program.