I think it looks beautiful! :D
As for the sleeve, you can attach one to the back by hand. Use a strip of fabric about 1 1/2" wide by the width of the walll hanging. Turn under one of the long sides and both of the short sides. Sew the bottom part onto the wall hanging by hand. Usually you sew the top part underneath the binding, but since you already have the binding on, you'll have to sew that part on by hand also. Don't do it right at the top, do it as close to the top seam as possible.
My husband got some 5/16" round dowels to hang them with. Cut the dowel just a little wider than the wall hanging and put a slit on each end. Then get some string, tie a knot in each end and thread that through the slit on each side and you're done! :D