Classifieds Facebook share icon for product

Hi,

I'm using your classified plugin.
Just to know how to insert a facebook icon to share the product.
If possible to insert the icon manually or using a plugin.
Please look at picture enclosed to understand better.
http://i255.photobucket.com/albums/hh153/mcbrandsstores/second/a760e990.jpg

Thank you very much.
Simone