Metric Miler basically said what I wanted to say (i.e., that the current 800m trend is for former 400m guys dominating the field, and gone are the days of Coe et al).
But you do have a point - the OP's muscle fibers and body makeup is probably are not conducive to training like a pure 400m/800m runner. Maybe his body type will be more receptive to more mileage. But frankly, I doubt that as well.
The Kenyans pick their distance runners at an early age based on their 200m speed, since endurance can be taught but speed cannot. And 800m requires an abundance of speed.
If OP is set on the 800m, well increasing his mileage will only add more pain and tedium to his training schedule (I mean, who enjoys 10 mile aerobic training runs?), which may in fact actually make him slower by taking away what little speed he already has.
His other option (which I suggest) is lots of strength training, building muscle mass, losing fat, short fast intervals, etc. That sort of training is fun, is probably healthier, and obviously more physically attractive to the opposite sex. Better than starving yourself and spending 1 hour on the road alone running along at 7:30 pace.