If that bug is fixed I think this will be a 95% perfect!
(100% will be if the plugin can add the XMLNS attribute also :P)
Phoca Site can do the trick (there are two plugins, one content and other system - because it is not possible to add open graph information by system plugin and XMLNS parameters by content plugin into Joomla! output).
So, for adding open graph information, use Phoca Open Graph Plugin:
For adding XMLNS parameters, use Phoca Site Plugin:
I am not sure, if I understand this correctly:
"if you have a site here you have a module of blog articles in your main page, the "og:title" will be set with one of that articles titles."
Will be great, if you can describe more details about this issue in Phoca Forum - http://www.phoca.cz/forum/
Thank you, Jan