Spoonflower is one of the better options. There are other digital design places as well. Depending on how the fabric is going to be used/what the original design was, it may make more sense to design something similar but so that the repeats work better. Fabric design is a skill set of its own.
We can also transfer images and print them at home in various ways -- it depends on your printer what you do and how to treat your fabric. There are fabric transfers sheets you can buy through the mail or at stores -- even office supply stores. One of our members here recommends going to a t-shirt/silk screen shop and has her transfers done there. You can iron on fabric directly to a piece of freezer paper and feed it through most printers, and you can print over existing prints or use solids.
I don't have a color printer and so I would have to go somewhere else. I think I'd like the Spoonflower option best.