Even those with CS6 are not particularly thrilled with the retina MacBooks from what I've read. Adobe will be updating Photoshop CS6 but they've made no commitment beyond that.
Now would be the best time you'll ever have to upgrade. Beginning 1/1/13 you will be ineligble for upgrade pricing at all.
And...until 8/31 you can move to Creative Cloud for only $29.99/month for the first year. After that it's $49.99.