Bedroom Reading:
www.gordonpirie.com
Scroll down to "Running Fast and Injury Free"
Click on the updated version,
Click on "Download as PDF"
<Firefox> allow popups, then click "Download as PDF" again.
As for your initial question, I'm really not sure as it's not my forté, but I imagine that by training specifically for a mile run sub-7:00 is very possible.