I cant see quite where the whole is but what i can tell you is if it were me i would repair it and keep an eye out for a replacement to keep in stock
First off get the sucker on a wire wheel and get all the corrosion off and back to clean metal
then line the inside of the pipework with masking tape or similar so as you cant 'see' through the hole any more
go down your local hardware store or motor factors and get yourself a pack of JB WELD
its a form of chemicle metal/epoxy resin but its the mutts nutts (once did an over night repair in the middle of nowhere on a motorcycle exhaust studd, it had stripped out completely so i just popped it back in with jb weld, let it harden over night, tightend the nut up in the morning and didnt need to worry about it again in the 4 years i owned the bike)
Anyways back on topic now start to rebuild the missing metal with the mixed up JB WELD, it may take 2 coats as you need to get the repair thick enough to withstand being clamped with a jubilee etc (try to do it in a cool area or it will run a bit if it gets warm) if so make sure you key the first coat well, go right the way round the whole hose tail with it making sure all pitting etc is filled well and it is worked in the whole way up to give a good base to work with, allow to harden over night then sand/file back to a nice smooth finnish with rolled end, remove the tape from inside (paint thinners will remove stuck on tape) and robert's your fathers brother and fanny's your aunt
bolt it back on and jobs a goodun
hope that made sense?
