Where did you buy it? If you got some cheap generic thing off eBay then the ink is probably just food coloring and water. Image Specialists is one of the bigger names for aftermarket ink, and there are several resellers in the US. You may also need an ICC profile for your printer to get the best results.
Personally I think the WF1100 color output is bad anyway, but plenty of people here find that it is a very good printer.
Personally I think the WF1100 color output is bad anyway, but plenty of people here find that it is a very good printer.