Your best bet will be eBay. AB has essentially stopped making the software, and charges an arm, a leg and one more body part (your choice) for the software.
Don't forget to get some communication gear (KF2, etc.) so that the software will talk.
And even if you master the beast, no modern PLC thinks in the same way the the PLC-2 does. It was good in the early 80's, but then, so was DOS.
Your best bet would be to put the thing back where you found, and get something from Automation Direct, or a simululator from The Learning Pit.