Complicated Podcast Recording Question

First of all, sorry if this is the wrong forum to post this question in. I wasn't quite sure where it best belongs... Possibly hardware/software... I'm really not sure.
 
So anyway, I have this podcast idea that I'd like to attempt recording, but I'm having a little trouble wrapping my head around how I would record it. Here's the gist of it. I want to record, in real time, the audio coming out of my music computer while I'm playing it so I can record me making music in real time. Along with that, I also want to record my voice. I also will have a friend who will call in and I need to be able to hear him talking to me, and he has to be getting recorded too. That's it.
 
So IDEALLY I'd end up with 3 separate audio tracks. #1 is the "what you hear" audio from Sonar on my music computer, #2 is me talking being picked up on my microphone, and #3 is my friend talking coming through either a phone or skype or something. That way I can mix them all after and edit if necessary.
 
Now I'll tell you what I have... My computer with Sonar Platinum has a Focusrite Scarlett 2i4, so I've got 2 ins and 4 outs. I have an XLR mic. I've got headphones. I've got a good quality laptop with an older version of Sonar on it that I'd imagine I can do the recording on (perhaps I'd need another audio interface for it if the onboard audio can't handle all of this).
 
How would I need to route everything to get my desired results? Any input would be greatly appreciated. I'm going to be on pen and paper trying to imagine the routing of it all myself, but I figured it would be worthwhile to at least ask and see if anyone has any ideas.
 
Thanks!
 
 

Thanks Brando. that looks like some wild stuff haha, but I'm gonna check it out. I'm so used to doing things with literally 1 input and 1 output so wrapping my head around routing stuff is so hard. Looks like an interesting piece of software though for doing what i need.