Run more. Much more. Mostly slow, sometimes fast. You're talking about sustaining 6 minute miles for an hour, which is starting to approach the bottom of elite level. That would put you at 1:18ish for a half marathon, which is a very respectable time, and often would place you on or near the podium for an age grouper.
You would need to ramp up to where you are consistently running 5-7 days a week, in the 50-70 miles per week range. This would probably take close to a year to do injury free. Once you get to that point, you can start adding in higher intensity speed work to get faster overall.
You may not be able to get to that point. Your natural abilities may not be sufficient to get to that speed. On the other hand, you may be a natural and get to that point in less than a year, but I can guarantee that running 14 miles a week will not get you there. It's the day in day out consistent mileage that brings gains in running.
Also, you do not state your height or weight. Weight is also very important in running, as being lighter can be critical to moving faster. I've seen some calculations that show every ounce less in your shoe is somewhere in the neighborhood of 2,000 lbs of lifting that your body doesn't have to do. Now translate that to body weight.
Apocryphal lore is that for every pound of bodyweight that you lose, you gain 2-4 seconds per mile of pace (Dependent on personal running efficiency and other factors). So if you lost 10 lbs, theoretically your pace should go from your current 8:34 to 8:14 per mile for the same effort.
But the biggest thing is going to be safely increasing your volume, then gradually adding in the speed work.