Your thoughts on my dilema.

Well, if you're going to replace your computer in literally a year, then you can:

a) Get a cheap disposable laptop that you can pass on to relatives or siblings next year when you replace it

or

b) Build a good rig and
i) Keep it as an additional computer (not sure why you'd do this, as you've stated the Macbook would be your main comp)
ii) Sell it, which is much easier than selling the aforementioned cheapy laptop.

My thoughts, at least.