So, that’s your solution for now.
First of all, download this module.php file, customized with G+ added options.
Thank take this G+ icon, made by me. It’s not as cool as others in extra-nav collection, but the difference is not really critical, as you can see. If you check it out on this site, it looks cool…
Ok, now you’ve got two files that are needed to be put in extra nav folder. Here’s screenshot of how you should do it: