I agree with Dave there-- have a new one made. You may be able to repair the old one. SS work isn't cheap but it's always feasible. Price-shop it round where you live. If you can't make a drawing, take the guy the old fitting-- he can interpret it. Don't skimp on scantlings (relative thicknesses, bolt sizes, etc). There's no need to make it grotesquely oversize either.
I'm having a new tack fitting made for my boat too, as the PO smacked a few too many pilings with it. This gives me the chance to get rid of the H-25's hideous center-leg pulpit too and go with something better looking and more versatile (yay).
I like hex-head bolts, though they make it look like Frankenstein's monster, because they're easier to apply torque to than a Philips or (worse) slotted head.
Remember to bed it down properly. That thing takes a lot of strain on all angles and should be swimming in 5200 when you bolt it down.