@
norahfields
Buy the retina. HDD is the problem in your case, since it's slow. And PC with 2 TB HDD will be slow as well, since it is still just and old mechanical disk.
rMBP uses flash storage, and everything works like it should. But you could also try with replacing your HDD. Bump it up, put SSD inside and enjoy the ride. You will save money, and the upgrade speed will be awesome.
But it's still and old macbook, with usb 2.0. I would wait for WWDC, and then purchase new retina MBP.
But if you can get a current retina MBP for a decent price, I wouldn't think twice. It has all the bells and whistles you need.
Just go to any store with apple laptops, test new retina out and see for yourself. Best possible solution to your problem.