I have heard of 2 solutions but not tried either, but you may want to investigate further...
This is supposed to work - the plugin is free but you need to buy the script in the second link:
Code:
http://wordpress.org/extend/plugins/social-networks-auto-poster-facebook-twitter-g/
http://www.nextscripts.com/google-plus-automated-posting
If you are in the USA or India there is a workaround method that uses SMS:
Code:
http://www.warriorforum.com/warrior-special-offers-forum/471897-eureka-we-did-what-auto-posting-google-wordpress-plugin-google-plus-poster.html
As i said, i haven't tried (or even investigated properly) these solutions, but it may be helpful...?