See Link Below:
How can I make this basic PWM more advanced ?
- Take it to the next level that is better, saves more energy, can take more Amps,...etc...
- Make it the best PWM for a small 2x6V 0.04A DC motors...takes at least 0.1A when build.
Simple and dirty Pulse Width Modulation (PWM) For Motor Speed Control (!!! 0.2A max Amperes !!!)


http://www.easterngeek.com/2008/06/simple-and-dirty-pulse-width-modulation.html

 

I don't see what your problem is, you seem to of already found a PWM that can power double the output that you need.