How can I best record music with an external mic onto my macbook air?

I had an old mac monitor type computer that I used for recording music, but it was slow and non-portable, so I bought a macbook air. I just tried to record using the same set up,(but with the laptop) and it won't recognize the external mic. I'm using a Monoprice 600800 mic connected to a mixer (monoprice 615808) that plugs into the audio port of the computer and I'm recording using N-Track.

I just read you have to connect with a three ring jack or via USB. What is the best adapter to get? Should I get an adapter for the mixer thats USB or three ring jack, or just ditch the mixer alltogether and get a USB adapter to connect directly to the Mic?