So I post guitar tutorial video's on Youtube, which require guitar and vocal to be recorded. However, the standard mic built in to my laptop (I have a 13" Macbook) is less than I want in terms of audio quality, so I bought an external microphone and a Griffin iMic. Now, the problem I have is that my microphone doesn't pick up my voice and my guitar, and there is only one port on the iMic for recording, meaning I can't record vocals and guitar simultaneously. I can't record them separately, because I do a sort of commentary, which is hard to record over the top, really hard. So I'm thinking, do I need a better external mic, which will pick up both vocals and guitar, or do I need an audio interface (I think that's what it's called) that can simultaneously record both guitar and vocals, by having a mic plugged into it for my voice, and my guitar plugged into it also. Please help.