Speed Work and Weight Training instruction

I got up at 8:00am, and found out it was a little early if I just wait for the 8:40am class. So I decided to run a short interval run before class. As a registered tester, I got a pair of test shoes from New Balance yesterday, WR805. They are designed for speed workout but not long distance running. They are very light weighted.
I went to track and run a 800X3. Before start running I did some dynamic warm-up and a 400m slow run warm-up. The times of the 3 800m are: 4:35, 4:57, 4:38. Between the first and second 800, I jog in 13min pace for 400m, and between 2nd and 3rd one, I walked 100m due to the time limit. My ideal time should be 4:30-4:40 for 800. and slowly jogging 400m for recovery between each 800. I am going to do interval again later the week, try to make 5 to 6 800m, and within ideal time.

During the class, we learn many weight training specific for runner. I feel it is very useful. I have balance ball and dumbbells at home, I can start to do to train my ab and lower back.