Can I run a half-marathon by adding in a few runs with my regular exercise?

Tamsy's Question:
Hi there,
I'm wanting to run my first half marathon on 22 Sept (Blackmores Run) and wanted some advice.
I currently play winter soccer on Sundays (starts in April and goes until late Aug), train every Wed night for 1.5 hrs.
I go to bootcamp 4 mornings a week at my local gym - Mon, Tues, Thurs & Fri.
Tuesday evening I will start training with a running group for about an hour.
Wednesday mornings I will try and go for a run...
Please advise what I need to do differently in order to achieve my goal to complete the half a marathon.
Kind regards...........Tamsy

 Lee's response:
Hi Tamsy,
What exactly is your goal? Is it to just complete the half marathon and you have no goal time OR do you want to actually train adequately for it and achieve a time.
There is no doubt that you are very fit from your soccer, 4 x mornings of boot camp and your 1 x 60mins running, but this only has you fit and not half marathon conditioned fit. Our half marathon programs are 12 weeks and you would need to be running a minimum 4 - 5 days a week. The half marathon is 21.1km's and will require you doing some runs at least 3/4 in distance so you can be confident of completing the event.
The half marathon is not only an endurance event due to the distance but there is a number of tough hills in it that will require you to be strong so basically you would have to become more running focussed in that 12 week period if you want to do well.
Of that 12 weeks, we require 6 weeks (42 days) as a minimum to safely say that you are prepared minimally to do the race well.