I got my 83' gtv6 fixed before, both the door and the ignition. They are 2 different kind, the ignition is just like a normal key and the door is a special key like the one used in late 90's mercedes. Alfa stop using that kind of key system in the Milano.
I just order a blank key from IAP for the ignition (cost less than $5.00 each) and give it to my locksmith to cut it ($3.75 each). Easy and no problem at all.
The only problem is the door lock. I try so hard to find out what can I do about it and no one seems to have an answer. Even the Great Shop in Toronto which starts with the "P". The only place I finally find is a Alfa Romeo dealer in England and they need to sell me 3 used replacement locks (both door and the trunk) with 2 keys which cost me 450 EURO. I told that situation to my locksmith and that's what he suggested to me. Find a used door key from different GTV6 and take both door and the trunk locks out for him to recode to accept the new old key. Took me about 3 weeks and cost me around $250.00. If you interested or want to talk to the locksmith, I can give you his location and phone #. He is in Markham, Ontario. Acturally, the locksmith didn't do it all by himself at that time, he had to call his dad for help. You know, old man always a little wiser.
It might be easy for you if you can take those broken pieces and a door lock to the locksmith. It might cost you less than $10.00. Good luck.