Here are some alternative ways. The first two presume that you make the DVD outside the MBPr and then you would use MPEG Streamclip to rip your file from the DVD. That could then be edited in the NLE of your choice.
If you have a DVD player/recorder, you can run the the camcorder output (or a VHS player) to the player's input and dub it.
If you don't have that equipment, and you only have one or two tapes to digitize, the cheapest way would be to send it out.
If you want more control and quality and potentially have enough projects to justify the cost, take a look at one of Grass Valley's analogue-to-digital converter boxes. You run those to the laptop's FW port. That's the best way, if you're going to be doing this much in the future.