unfortunately, it's not as easy as it seems.
code form website that you linked above doesnt work well in 1.6 and also in 1.5 generating some problems, - it's for prestashop 1.4.
To generate full detailed and working tags it's necessary to modify a lot of things.
in this case is necessary to define code for each "type" of shop page, like cms pages, manufacturers, product pages, category pages etc.
modification like that needs a lot of customization in the core, so im more than convinced that no one will do that for free. unfortunately.
It will be much easier if you will use addon like http://addons.presta...graph-tags.html (doesnt work with 1.6) or mine http://mypresta.eu/modules/social-networks/facebook-open-graph-tags.html (it works with 1.6)