Do you have a voltmeter? You can get one off eBay for about 10$. Something that can also read amps would be nice.
The Voc and Isc might be different than what it can produce under load. I'm assuming it will be rather low voltage, so perhaps you could rig up a load a several flashlight bulbs, wired in either series or parallel to put it under an appropriate voltage? You could then measure the amperage with a DC clamp meter. Multiply the volts its running at and the amps its producing to get power. A regular meter measuring amps might work, but it will need to be in series with the load.
BTW, this isn't some Plutonium core device you smuggled out of CalTech when you worked there is it?