where can I buy an outside hand rail for a disabled ramp?
Answers:
First, check with your community's building department to see what the local building code requires. Commercial style ramps have guard rails that attach to both sides of the ramp along it's length and anchor in ground. The guard rail will extend a short distance on level ground before the ramp begins.
Your plumbing supply store may have galvanized pipe which could be used as a railing. They will bend it to the shape you want. Muffler pipe works well also and is a little easier to work with. Or your building supply store can order one for you if they don't have railings in stock.
Other answers:
home depot
home depot
I don't know if this site sells things like that, but they do have some nice things.