You can run it off of the internal hydraulics, but the loader will be very slow.... it'll slowly drive ya nuts. Yes, pto pumps are readily available (I assume that is what is/was on it). Trouble is, it ties up the pto for other uses. What I would suggest is to go on the hunt for a front mount pump which will run off the crank on the motor. Try Ag Parts First, LLC.
If all else fails, I have a good pto pump that I would part with. 
                                        Cal