CUDA is not currently supported on mac OS. Get a Macbook Pro, and make sure it has a dedicated GPU (look for discreet graphics, ATI, Radeon, terms like that). Try for at least 1gb on the graphics module, and 8-12gb ram. Other than that, shoot for 256gb or greater ssd internal drive.
Since I don’t know your exact specs for working conditions, you can swap out that SSD for an HDD of 1tb or greater, 5400rpm, but boost your ram to the max if you’re doing any live capture, and use the HDD for that.
If you’ll have some power where you work, you can plug in some RAID drives via thunderbolt or even a Dock that plugs into thunderbolt. This will allow you to dump your files to faster drives for your actual editing workflow. With a Dock, you could have several RAID and purpose them all.
I use a 2008 MBP with a 2.16ghz processor, 256mb gfx, 4gb ram 15inch, and I’ve modded it to carry 1x5400rpm hdd and 1x7200rpm hdd (removing the cd drive). I use an Esata Expresscard and the firewire ports to run several RAID drives. I edit 1080 prores proxy video just fine. My compressions take a while though. I’ve augmented that by outputting a Prores LT or full 422 to my internal HDD 5400rpm, or a network drive (hardwired net) and using compressor to do audio on my comp but video on comps I rent at a studio\lab. That way I can only rent what I need for a short time, save some moolah, and provide excellent quality. It’s fast enough for me. I put out 2-4 projects in a week to 2 weeks, with full edits, and I dump to DVD\blu-ray. Occaisionally, I’ve been asked for digital only, which allows me to still use DVD’s as a transfer medium. I burn with external burners and have a duplicator. I archive my work by using RAR and .iso images. I start them off as sparse images.