If you're using Blubrry stats, you can get an estimate of your total audience by taking a look at your download numbers after an episode has been out for four weeks. It's likely that, after four weeks, all of your regular listeners have downloaded a new episode.
It's harder to say with web analytics, as not all website visitors are guaranteed to be listeners to your podcast. But, you may be able to use these two stats (download numbers and web stats) together to paint a larger overall picture of your show's total reach.