HooteSuiteAmong many other services, HooteSuite can automatically post content to your social networks via an RSS feed. You can read about how to do that here.
RSS GraffitiA Facebook-specific application, RSS Graffiti will take your RSS feed URL and use it to automatically share new posts on Facebook. Learn more about the app here
With any of the above services, remember to use your Blog Page's RSS feed. Cheers!