Where did iMovie go ?!

I rebooted my macbook white, the version one step lower then the new macbook white now. And found that I could not find iLife on it, because the main purpose i used iLife was to make videos on iMovie, but now that is gone. And i dont want to have to buy the new iLife. Also, my macbook cannot upgrade it's version, it just says there are no new versions, it just stays on version 10.5.8

Please help ! ? 🙂 x