Found the solution;
Edit this file: google-author-information-in-search-results-wordpress-plugin/class.filter.php
with target=”_blank”
if($options['hide'] == 1) {
return $content.='<a style="display:none;" href="'.$gplus_author_link.'">Google+</a>';
} else {
return $content.='<a href="'.$gplus_author_link.'" target="_blank">Google+</a>';
}
}
}