Check out this recent topic for some ways to get traffic to your shop:
http://www.t-shirtforums.com/showthread.php?t=3191
I don't think the flash is helping your sales any. It just makes it harder to shop and doesn't add any functionality to your store. It also will hurt your position in search engines because there is no text on the page to pickup.
Since you live in Chico (I was just up there a couple of weeks ago), you may want to try marketing your t-shirts around the college crowd. Wear your stuff out to the bars and around campus to get it seen. Maybe advertise in the campus newspaper?
I don't mean to sound negative, but right now, there's nothing that really "stands out" about your site or designs. Offensive has been done and done well by many other sites, so if you're going to enter that market, you have to really do something different or work 10 times harder to advertise and market yourself.
Before you start selling t-shirts, I think you should have an idea of who your target market is and how you plan on reaching them through advertising and promotions.