Am I getting a good work out?

For the past couple of years my friend and I have have been faithful walking partners. We walk about 3-6 miles about 4 times a week outdoors and up and down a lot of hills in the freezing winter or sweltering summer. It takes us about 12 minutes or so to complete each mile. We really saw no results with this activity, we felt good but not as toned as we’d like to be so we decided to start doing some exercise videos 3 times a week and continue to walk 2 or 3 days as well. So we started doing the a Wii exercise program, and alternate with a couple of Billy Blanks Tai-Bo dvd’s (switch it up a little, I heard you shouldn’t do the same routine all the time). Those work outs get pretty intense and are about 45 minutes long. Some include weights and stability balls. We sweat, get fatigued through out the video and a little short of breath but we can finish them with out being exhausted and we have yet to be sore the next day. While doing some of the ab workouts and squats we always say “we’re going to be sore tomorrow”, but we never are. Neither one of us are over weight we just want to be physically fit and toned.

So my question is, do you think we’re getting a good work out or should we do something more? Any advice will be appreciated!