Ch'i

It is doing something, but you should be working your whole body. Add some light weight (10 lb.) to your workout, and target the major muscle groups; Chest, back, squats work pretty much every major muscle in the legs, bicept, tricept, and abdominals. Work those out and you'll stay nice and healthy. Also, try going out for a jog for 10-15 minutes right after you workout.

Here's a mock-up weight training routine:
Dumbbell Flys- 2 sets, 8 repititions
Bent Over Row- 2 sets, 8 repititions
Shoulder Press- 2 sets, 8 repititions
Lunges- 2 sets, 10 repititions
Squats- 2 sets, 12 repitions
Bicept Curls- 2 sets, 8 repititions
Tricep Dips- 2 sets, 8 repititions

Abdominals: The abdominals are composed of 5 different muscles; transverse abdomis (underlying front muscle), upper abdominals, lower abdominals, obliques, and the lower back. You can excercise these daily.

Mock-up:
10 Crunches (keep you tounge on the roof or your mouth to keep your neck muscles properly aligned, and do NOT pull your head with your hands)
10 Leg Lifts
10 Bicycles
30 second Bridge Vacuum (Get into the pushup position, and rest on your elbows. Straighten your body, and "suck-in", trying to pull your belly button to your spine. Hold this for 30 seconds.)
10 back extensions

Do the weight training every other day with about 10-15 lb (start with 10). Then do some sort of cardio immedeately afterwards for at least 10-20 minutes. On the days you aren't weight training do 30 minutes- and hour of cardio. This regiment will keep you lean, and give you a very healthy cardiovascular system.