Check around your area for an industrial hose supply house.
I buy mine from a local shop that caters to forklifts and big rigs, and they have a huge supply of all grades of hose.
In case you can't find anything in your area, perhaps you can mail order what you need from the place I go to.
www.hose-man.com
I will look around for the exact ID size for you, I have a picture of the hose I use around here someplace.