(I can merge if you like, but as the other thread is not currently active it is fine to just leave it linked)
From the other thread, you have the birth of her son as in Larino from the Canadian/shipping records, so the first stop would be to obtain his birth record, and then see if there is a marriage record in the same area. If you have a LDS family history centre near you, the easiest way would be to order the microfilm as suggested on the other thread (this way you can check for siblings, etc).
Otherwise, you need to write to (I think) the "Ufficio dello Stato Civile" in Larino to obtain a copy of his birth certificate (and possibly the marriage). There are plenty of form letters around, but you may want to ask on an Italy-specific genealogy forum for advice as I don't have personal experience in writing to Italy. If it's anything like France/Belgium, expect a long wait and occasionally just no reply at all. If you can find an email, turn around may be quicker but you still may need to send money by post (I've had some luck with concealed cash + international reply coupons for postage but money orders etc. may be a better bet).
Optionally, you could also obtain the English marriage certificate which will hopefully have his father's name.
Other notes:
The Canadian record actually says "M Mario Libbera Delpinto" e.g. could just be mother, Maria(sic) Libbera (maiden name? misspelt?) Delpinto. You can search here:
http://www.collectionscanada.gc.ca/databases/cef/index-e.html and get information about how to order his full file if you are interested.
Italian women are often on records under their maiden name (the same thing happens with some other European countries) - so for example if she'd come to visit him while he was in Canada she might not be under "Del Pinto".
