Hi Katia,
I wouldn't worry about the CTX cardio not being long enough - they are short, but pretty intense. Sometimes when I have a high energy day, I may do two CTX cardio workouts back to back. If you buy the series on DVD it's easy to do.
I agree with Deborah though - add weight training to lose inches. I lost most of my inches from lifting heavy weights and only walking for cardio. HTH