what should i be doing

im 23 always been a pretty good runner, stopped racing when was 17 for football. tryin to get back into. ive got a half iron man middle of this year, most recent race im 1.07 over 10 miles. swim 5 times a week and bike 4 on turbo. how much should I seriously be running to get the best out of myself? because at the moment im doing 6 every Tuesday with club and then racing sundays either 6 10 or half mara. and what times should I be working towards for the iron man.???