OHio,
As already implied by Paul, I doubt your stock hydraulics are up for running the rig, but then again I doubt any cat 0 machne has hydraulics up for the task, which surprises me it doesn't already have a pump, so it may be worth comparing what your machine puts out and what thet hoe needs. My guess is your machine puts out 6-7gpm and you need twice that to run it.
If your rig cant do it on it's own, I would look at what a pto pump and resevoir is from the manufacturer, northern industrial or Surplus center so you can factor that into the cost/hassle of making it work.
I assume it is only a 3 pt mount and doesnt have a sub frame?
Sub frame units are nice, but you will obviously have to weld /customize whatever frame it comes with, and these frames can really limit your ground clearance.
W/3 pt mounts, you can really only dig right behind you. ANy off to the side work will bend your drag links in a hearbeat.
So when you weigh it all, I have to say buy a used mini excavator..you will be much happier.