Well it appears that your biggest issue is hard drive space.
You can go about this in two ways...you can swap out the hard drive of your MacBook for a bigger one or get an external hard drive to move some stuff to that external.
You can fix your problem for about $80-$100 instead of building a whole new pc.
Well how much is it going to cost to get Windows on my Mac? which was the reason for me doing the build
btw I have a 2012 Macbook Pro