Thank you all for your suggestions.

Thanks pjz99, The E6600 is about $700 Aust. more expensive than the Athlon 5200 system.
Would it be $700 better, ie. noticeably better? If its just a matter of waiting a few more minutes for a render, I'll wait. I don't at present use anything like the highest quality render settings, though I am starting to use IBL with AO more regularly, which slows rendering quite a lot.

I can afford to get the E6600 or higher, but am I just paying for the fact that all new stuff is highly priced..
I remember paying $3500 for a P3 600GHZ system a few years back. Makes me want to cry.