The only thing Olivia mentioned about a band on her Twitter page was last July and she said "my sis & her band is here on tour!! having too much fun hanging with them!!!
"
So if you saw something like that, it wasn't on Twitter. haha Goshhh~ I really want some new music from her. Did anyone ever get a copy of the French album? Didn't it have a new song on it?!
[edit]
*sigh*
I just went on the French iTunes and it turns out the "unamed bonus track" was "If you only knew (world's end girlfriend mix)." It's a mix that she had on her myspace a long time ago. Not too spectacular. I'm sad it wasn't a new song. What a totally useless release for non-French fans.