It's very surprising to discover that 80s one-hit wonder Toni Basil (possibly the ultimate one-hit wonder!) released this fantastic track back in 1966, which was apparently popular on the Northern Soul scene. It was the title track for an underground movie she starred in, and the B-side to her first single, 'I'm 28'. The original vinyl sells for about $350-400. I think there's been a vinyl reissue - you'll notice if you search Gemm or MusicStack some copies show up for $10 (and are a split single with another singer).
'Breakaway' appears on the Out On The Floor Again compilation.
[Update: Breakaway video]
I haven't heard 'I'm 28', but I just discovered it's on a compilation boxset entitled Girl Group Sounds: Lost & Found. The link has listening samples, and it sounds like a really great song too. Considering that's my age, those lyrics are the most relatable I've heard in a while - how completely depressing! :D
Here's a bonus, just 'cause it sounds so cool:
Can be found on Living In Oblivion: The Greatest Eighties Hits, Vol 2.