Sound in? (how can i make my headphone port work as a mic/line in port?)

Hello, i have a MacBook Pro 13 Mid 2012 model running the latest OS X (Mav)

i looked in sound and it doesnt have a use headphone jack as a line in jack or anything so i hope it still works? i need this working if not any other way to get it to work or software that i could use?

thanks for your help!