exterior window decor and trim

I am looking for exterior window decoration and trim products. Particularly around the outer window fram, I believe the product is made of concrete and fibergalss, sould be wrong though. What I mean is like making a picture frame, but this time it is on the outside of the window, to be stuck on hte stucco around the window frame. I will be using this frame to decorate and give my house some style. Where do I look for this kind of frameing material? Once it is cut and stuck around the window frame, you will can either use the same house stucco to look like it it part of the masonary, or give it a different color than the house, to accentuate the frame itself. I do not know if I explained myself enough.

Thanks in advance.