BTW... be VERY careful if you have your volume turned all the way up. As you figure this out you could end up BLASTING yourself through the headphones which is of course very bad for your ears.
 
That said, there is an option if you have indeed got the mic as loud as it can physically go (I doubt it but maybe). At the top of Sonar you will see some "Windows" style menus. With the one that says "Process" there is an option labeled "Normalize". If you "Select" the "Clip" of your recording (the little box with squggle lines that shows up as you record... just click on it once until it turns a light gray) then go to that menu and choose Normalize it will turn the Clip volume up as far as it can go without cause nasty noises (which is called "clipping" but has nothing to do with "Clips"... mostly).
 
The problem with that is it will also turn up the "Noise Floor" which is general low level noise like hiss or hum. This is why it is better to get the best input signal to start with.
 
I'm laying down for the night so the other guys will have to help you from here on out. I'll be back in the morning.
 
Good luck.