Youre doing a great combination or aerobic and strength training. A good amount of stretching is advisable, since the spin classes tend to shorten muscles.

I do lift weights as well. I try to get an all around workout. A good investment if you are into doing cardio workouts is a heart monitor. I received a Polar monitor as a gift. The strap goes under your shirt, around your lower chest area and the watch gives you the readings. It helps me have better control of my target heart rate.

Out of curiousity, how much have you been charged or were you going to be charged for personal training? The gym here has some outrageous rates, and I didnt know if it was a universal thing.