I did some research and see that you are not tagging your designs to take advantage of the CafePress Marketplace.
For instance your robot hand design (I like that one alot) I type in the marketplace "robot hand" which produces only 2 pages of results and your design is not there. That can only happen if you are not carefully tagging your images, the Marketplace uses those tags for its search.
You also only offer your designs on a few items, I have learned that what you might think is cool does not mean that someone else won't want your item on a mug or a mousepad. You need to add your items to ALL products, work on your tagging as well as your copy within the store itself.
You haven't given CP a chance yet in my opinion. There are plenty of threads here and on the CP forums that will give very specific action items for you to take to make the most of what you have started.
Good luck! Your designs are unique and will appeal to lots of folks
