I didn't provide you with enough information. I was still running after my PR's and wasn't starting from scratch before my 15 weeks of Half Marathon training. I consider my "official" training to begin when I start track workouts.
As for training intensities, buy Daniel's book, run a mile on the track as fast as you can, and then use his VDOT formula to determine you training intensities based on your current mile time.
Run your workouts based on your current fitness, not your goal time. As your fitness improves, then increase your intensities.
Hope you find this useful. It works for me, but I'm just trying to stay in decent shape and race around 6min pace for a Half.