Noosa Tri in November and starting my training over again?

I am entered to do the Noosa triathlon in November and have 5 months exactly to train. I started training in January and have recently come back to it after 6 weeks off for personal reasons (and possibly overtraining).
What would the best training program be now? I managed to complete 16 weeks out of a 20 week beginners balanced program and now feel as if I should start over again because of the long break - could someone please suggest the best course of action.
The race in November is my first triathlon and it's Olympic.