Howdyheidi most of the online stores have stencils. I like the Tim Holtz ones and Crafters Workshop stencils, prima also has some good ones. The one I used on my card is a prima finnebar stencil. Look at Simon Says or A Cherry on top, do a search for stencils and pages will pop up. I have also purchased a few from Amazon....they have just about everything. I usually compare prices and go with the store that is cheaper when taking shipping into consideration.
I use inks a lot when I stencil but for stencil bump technique paint works best because you want the bottom layer to stay, but you should try it with ink and see what happens. Maybe use archival ink for the bottom layer and then a very opaque ink for the top.