>General Running>Fartlek vs. Interval vs. Tempo
I've got a fever...
On your deathbed, you won't wish that you'd spent more time at the office. But you will wish that you'd spent more time running. Because if you had, you wouldn't be on your deathbed.
What you need to do is work on the speed, work on your ability to run at your lactate threshold. You should look into doing intervals, and hill training.