To update Twitter and/or Facebook on Google+, we have introduced a few ways, such as Google+Tweet, Google+Facebook or Extended Share for Google Plus mentioned here, and some others mentioned in the post 101 Google+ Tips:
The following will show you another 2 new ways — Publish sync and G++, which are both extensions for you to integrate Google+ with Twitter and Facebook, and even more.
1. Publish sync
Supporting Chinese, English, Japanese and many other languages, Publish sync is a Chrome extension that offers a mutual synchronization among the websites Google+, Facebook, Twitter and Plurk, which means that you can post on any one website and sync to the other three.
When syncing to Google+ from the other 3 websites, you can choose your circles, but only text and links are available, and you can’t sync posts to your Facebook fan pages.
Workable for both Chrome and Firefox browsers, G++ is an extension for you to integrate Twitter and Facebook in the Google+ website.
You can read your Facebook and/or Twitter timeline updates, you can post to Facebook & Twitter directly from Google+ (even no need to post on your Google+ together). What is more, you can like or comment on the Facebook streams, and you can also reply or retweet the Twitter messages.
But it seems that this extension only works when your Google+ language is English, and any other languages (at least Chinese during my test) including in your posts will be garbled.
Between the above two extensions, I prefer to use Publish sync to sync Google+ posts to Twitter and then to Facebook with SupaSync as mentioned before.