please help asap imac audio in?

So bought a capture card and one of the required things needed is using a audio in as the imac 2013 does not have a audio in what's my next course of action to get a audio in port for my imac to get sound from the source going to my imac?

what's a reliable one?with good quality

https://www.youtube.com/watch?v=d26bTPJd6Xg

trying to do this would i with that piece needed u say to order?

AppleNewton said:

i hear the Griffin iMic has been really reliable.

Click to expand...

ok thanks i was directed to that by a friend,can you look at the video posted above and tell me if that's what i need thanks,i have everything else but no where to plug it due to only having a head phone jack

http://www.amazon.com/Creative-Perf...=1422581512&sr=8-3&keywords=mac+usb+soundcard

would i be better offwith something like this for better quality etc or no?