hmmm, 26.6 seatpost: could be Aelle if it's Columbus, could be metric Reynolds 531 (but that would be very weird for an Italian bike), or could be a straight-gauge seat tube. In any case, the damage was done by something like running into a tree, NOT because of any equipment substitutions. You could take it to a frame builder and see if there's any hope of pulling the headtube back into original angle, but I wouldn't hold out a lot of hope. See what a reliable LBS with frame expertise has to say, but be prepared to part it out