You have enough time to prepare, focus on mixing up your training do long slow runs, 5, 10, 15 kms get a time. Interval training; work, rest, run; 5 x 400m - 5 x 200m intervals with a 1:2 work rest .  Fartlek training; run for and hour mixing your speed for a given times, even add a brisk walk if required and circuits that incorporate cardio and strength exercises that last between 20 minutes and 30 minutes.

If you commit 4 - 6 sessions a week to this you should be well prepared.
 

The Commando