I have the exact same 'dilemma'
I've recently bought my MacBook Pro Retina 13" and I was working on my thesis in MS Word on my old white MacBook (2007). I did once got iWork '09 as a present on a disk, but I've lost that one

.
So now I've already been thinking and puzzling for two months about whether to buy Pages '09 or not and work with that program on my MBP Retina (hoping for a free upgrade). Or I keep working on my old white MB and leave my precious new Retina alone until I graduate - somewhere this year..
We have to decide whether this investment will be worth the 18 (in my country) or not. The more I think and the more I wait, I'm better off by just buying Pages '09. Apple already gave me a stab in the back by dropping the prices of the Retinas (for my version 250), four months after they were released and two months after I bought it

- and no I couldn't see this coming, it's not like we're talking about an iPad or an iPhone, anyway. So I'll survive another 18..
If you can wait another month.. week.. couple of days (we just don't and won't know) than keep waiting. If you cannot wait and keep searching the Internet hoping to find an answer - like I did the last two months

- then just buy Pages '09 because you won't find an answer until the day Apple announces/releases iWork '13..'14?.. '15?..
Well, I guess I'm going to follow my own advice - this time

. Good luck and have fun with your new Mac

.