After a few days of shooting I've realized the audio is pretty quiet, and I'm wondering if that's normal. I have an azden sgm1000 or something with a foam screen and then windscreen that's connected to xlr adapter on GL2. I try to keep the audio around the circle about 3/4 up the audio display bar on the GL2. Have I been doing that wrong? Is it supposed to go to the top? Or is it something that just needs to be brought up in post?

as long as the qualities fine, i would assume you can just fix that in post.

I agree with KC. You should be able to increase your volume or gain in post. Just make sure to add a low pass filter to eliminate any hiss you may have in the background.
Was the mic on a boom? That could be a reason why your audio is weak. You could also check your gain settings on your camera and make sure they are up.
If it comes down to it you may think about reshooting the scenes again or possibly doing some ADR if increasing the volume and the filter don't get you what you want.

Mike

You can almost always bump it up enough, as long as it's recording low because it's quiet, and not because of signal problems, or because you're micing too far away. Do a test, to make sure it sounds alright boosted and listen on good speakers.

What do you mean by 'quiet'? Volume is always relative to the sound level of your system - levels are not.

-12 dB is the standard peak setting for professional work. Often, commercial albums (or songs on your iTunes playlist) will go quite a bit higher. This makes them seem subjectively 'louder' than your camera audio, but they will distort on high end systems. Don't worry about how 'quiet' it sounds as long as your levels look good. As I said, -12 (or sometimes -6) for peaks and -18 or so for most dialogue is a good starting point. The end viewer can always turn up their TV.