Where can I find steering wheel and horn ring???

You can fix the wheel if you want to. I'll bet the cracks are in the plastic and the metal supporting it is fine. Just V out the cracks and fill 'em up with PC-7 epoxy. Then sand and file to the proper shape. Prime and paint. Do a Google search for steering wheel repair and you'll find many informative articles. You'll be surprised how good it will come out.
I've seen a few horn rings for sale on E-bay.