you have the dreaded heater core leak. the heater core is a small version of a radiator located behind the dashboard on the passenger side used to provide heat to the cabin when needed. the part doesn't cost much but it's a bear to replace. in the short term you can disconnect the hoses running to the heater core and run them back into each other, bypassing the leaking core, but you'll have to replace it eventualy.
antifreeze leaks can be more dangerous than you think. we had a small heater core leak that went unnoticed until we went on a long road trip. about three hours into the trip my wife, who was sitting in the passanger seat with the windows rolled up, had a grand mal seizure. very scary. and she has a cdl so she automaticaly lost her job for 6 months and can't drive any vehicle for 6 months.
common anti-freeze is a veritable soup of toxic chemicals, although up to now i've never experienced any problems even though i've changed three cores and a couple of radiator hoses in the past two years on my vehicles. we think it was the duration of exposure combined with lack of ventilation, or worse her sole source of ventilation was thru the saturated ventilation system. The link to a poison center sheet on one of the worst componets of anti-freeze is
http://www.iowapoison.com/index.asp?pageID=155