Forget about the Mk 2. Since you do not have any camera now, I suggest you do saving up over the next 2-3 months and go straight to the 5D III. This will save you from saying "Haiz I should have bought the newer version...." a couple of months later.
If you die die need a FF cam now, just lookout for any used 5D classics in the resale section. This camera is not much different from 5DII, and I really mean NOT MUCH, based on my own usage. I have also sold 2 of my own 5D to professionals who sold their mark II for the classic and it came from their mouths (I am not 1 though). If you want to do video, renting or buying a dedicated video camera will be a better choice. Frankly spending over 2k on the 5DII at this current juncture MAY not be a really good choice, as it is widely considered to be still overpriced in the resale market.