Some thoughts about your page..
I noticed on your shipping page that you are using some kind of default Cafepress page with a huge list of rates for everything from CD's to buttons. If you're not selling any of this products currently, why list prices for the shipping? It might be confusing for your customers, and it takes way too long to read. Make a new page that just has t-shirt shipping prices.
Also, on that page it says "CafePress.com offers multiple shipping options..." Etc. Even though you have explained the Cafepress thing on your FAQ page, people who are not familiar with Cafepress might still be confused, because they thought they were buying from Teejunction, not Cafepress.
Overall it just seems like you have to make more of an effort to create an identity for your brand that isn't so centered on Cafepress.
As for targeting your market - Who is your market? That's the most important thing to figure out. The more defined it is, the easier it is to "target" it.
Try starting a Myspace page. Try asking your favorite bloggers if you can advertise on their site. And keep looking for new things to try. There is really a wealth of information about marketing both here in the t-shirt forums and all over the web. It seems like a lot of stuff, but just try one marketing tactic at a time, wear it out, then find a new one.
One last thought... be patient. You've only been doing this for a little while, and considering there are thousands and thousands of online t-shirt shops, you've got some serious competition. Stay focused and keep going forward, eventually the orders will start coming in.
Good luck with everything!