WHAT the hell happened to my garageband?

I dont know what happened to garageband on my macbook. I think it got deleted and every time i try install it again it keeps on saying this update is not nessarcary and it says something about ilife. Idk what is going on but all my songs are on there and i desperately need them . Idvd iphoto and imovie are all still my macbook and Garageband is not. If i uninstalled it wheres a website i can download it FREE cuz i had a free version of it and if it is not uninstalled what are the steps to get it back some of it's contents are still on my computer in ilife. HELP SOMEONE