The draincock is near the location you mentioned, check that before anything.
I would advise against stop-leak products, I have had bad experiences with them. I used some to stop the leak I had in my old chevy (freeze plug pinhole). It stopped the leak alright... it also settled on the corners of the water channels in the block which impeded flow and gave me an overheating problem (it would heat up at drive-thrus, red lights, traffic stops, etc.)
In lieu of stop leak products, I suggest some quick steel. Put it over the pinhole (if that's what it is) and let it cure. This is only a temp fix, but has served me well in a few situations when money was tight.