In my experience Country Curtains florals tends to look best in spaces that can take big volume window treatments.
Look on line or find a place that sells martha stewart. I think you might find something narrower or smaller scale. She has some very pretty linens.
Other option: I had a friend sew a narrow valance for my smaller kitchen windows. Bought just the fabric I wanted at JoAnne's , got the size that looked right, and I bet it was no more expensive than country curtains.

I would have a custom window treatment done. I would do a relaxed roman shade in a beautiful floral and have it mounted above the window to give the illusion that your window is taller than it is.