The theme adds facebook and twitter buttons unless you have disabled them. Though I realise we haven’t got a google + button yet. It is actually possible to add buttons to the theme’s default ones. There are hooks available to do that even if we haven’t fleshed out the developer docs yet.
Not sure about your plugin, not used it. But the fact that excerpts upsets it is a little bizzarre.
There are lots of other social media plugins around you could try.