I'm sorry but max heart rate is pretty much genetically set and declines with age. It's not really a good indicator of fitness at all, not nearly as good as your RHR is. Now you can use your max heart rate for setting training conditions and that's quite affective, though again, you don't want to do to much of it or with out enough base volume as you risk injury. What is your mile time may I ask?
BTW, RHR is a better indicator of fitness because a low RHR indicates exercise induced cardiopulminary hypertrophy, meaning an increase in both heart stroke volume and an increase in the precentage of the lungs vital capacity you use during exercise.