Go to
www.macmillanrunning.com
There's a free computer for translating race times.
Incidentally, I can run sub-2 minutes for 800m, but only run 76 minutes for half marathon. From my perspective your strength seems to be endurance rather than speed. For 1500 and 800m running you have to do some serious intense sessions, with low volume but high lactic acid production. For example, 500m (7 mins rec) 400m (6 mins rest) 300m (5 mins rest) 200m (4 minutes) 200m, with all the efforts at flat out pace, prepares the legs for the intensity of a fast, short track race. I would agree that there is also an important place for long track reps with short recoveries in addition.