You can't work on building power during the summer season when you're competing!
The time to work on building power is in the winter and spring- you'll want to incorporate more weight training as you decrease the intensity of the cardiovascular training. You'll increase the amount of weight you're using over time, leading into plyometric moves, then begin to taper down your weights as your cardiovascular training increases. The amount of weight training you've done over the winter and spring months will be sufficient for you to go through the summer, and you can apply the power training back into your cardiovascular training as you're increasing the intensity of the cardio sessions. By early June, you should have all the power you can build, focusing from June to August on racing.
It's a periodization program, pure and simple... if you don't belong to a gym, you will need to join one by November so you can begin the strength phase of your training. If you need more info, you can always PM me closer to November and I can help you to plan a 6- 8 month training program.
Koffee