If you have a good industrial supplier, hose supply they will have suitable hoses. Just take the old stuff and show and tell them what it is for. I have one 90o elbow hose and I simply measured it, went to the local auto parts shop[good one] and they let me peruse the Gates catalogue untill I found one. I had to trim the legs a bit but it was 90o and the right I.D.
As for the impellers what is the pump? Jabsco, Johnson, someone else?
For my Jabsco I just went to my local pump shop. Of course I had to phone around to find them. Some big marine supply houses, not retailers like WM., will have parts also. I don't know what you have in your area but someone like Fisheries Supply maybe.