Replying to Anyone have experience with server/render farms/multiple machine setups?

This idea came to me when I was looking at new computer parts. I have a decent computer now (i7 960 3.2 Quad, 12gb RAM) but my gpu is shitting the bed on me, and my motherboard/processor seem to hang unnecessarily long at startup which worries me. It's two years old and has done quite a bit and I'm content with buying a new mobo/cpu/gpu and stealing old parts to build a new beast. But why not use it until it dies? So I started to research how to wire two computers together to split rendering processes/creating a render farm. I had a hard time finding an answer for that direct question of just using an old cpu tethered to a new one, most suggested building from a few identical and new machines.

So a few questions I have are:
-would I be better off buying one new system (i7 3770k based, ~1,250) and wiring the old computer to it and hope I can split the tasks between the two?
-Is it possible to do what i'm thinking with two different computers, aka just using one as a bitch renderer to take up a bit of the work to speed up the process? What software/hardware setups would I need?
-would I be better buying a few cheap quad core server setups (2-4 depending on configuration, would like to keep the project sub 2k), replace the GPU on my current computer, and use it as the master to control the nodes?
-Links/guides/101 tutorials on how to get it all working/setup would be a huge help. Found some basic ones, would like a start to finish if possible just to see what I need. Especially when it comes to wiring all the ethernet together/creating a network. That confused me really quick.

I'd highly consider a switch to windows, but a linux based beowulf cluster is out of the question as I'd be using it for CS6 apps, cinema 4d, etc. If I could stick to mac, that'd be great, all my stuff is currently mac formatted, but i'm not sure you have access to the programs required that I found windows based.

Cheers for the help,
Jamie

PS: and because I know people will ask, "why the fuck do you want to do this/need to do this?" The answer is because I enjoy spending the time to learn about a subject I have no prior knowledge in, and figured this could be a cool way to spend some time and elbow grease configuring something that could be useful to know and practical to use for both now and future use. You can create a lot of power with not a lot of money building systems like this (mac pros are what, 5-6k for a 12 core machine? where this can give you 16 cores with an insane amount of ram for ~2k if done properly)