can i manually install metal?

Hello,

i don't exactly know what metal is but i do know its only supported on mac products 2012 or later i was wondering if there is a file i could download to install it or even if i could install it into my physical computer manually?

i want to know if my absolute only option would be to buy a new computer with it already installed, i hope i dont have to

also my computer is and

Late 2009 Imac running OS X El Capitan