Is the colour of the fluid green? or red, or does it smell? that's a definite sign that radiator coolant is finding its way onto your floor from the radiator, and if you let it continue and don't top up the radiator fluid inside the engine bay, your engine will overheat and die.
Sounds to me like a heater radiator leak, don't drive the car until you are regularly checking the level of the fluid in the radiator and get it to a mechanic to swap that radiator out for a new one.
and in addition get the mechanic to flush out the radiator fluid for new stuff.
Check the front passenger floor pan toward the fire wall.
heater core leaking
The radiator is located in the front of the engine compartment. The water tank reservoir is mounted to the firewall on the passenger side of the engine compartment.
Heater core
If your vehicle has a sunroof, the drain tube may have popped out of it's outlet. This tube runs down inside the roof support on the passenger side of the windshield, running down just in front of the passenger door behind some plastic. I have a 2003 XRS. It had a really musty smell that we traced to the front passenger side carpet. When I pulled the carpet back, it was dripping wet. The air conditioner drain hose had pulled away from the firewall and was draining into the floor pan. I replaced the tube into the hole and have not had any trouble since.
Floor at passenger side? Could be heater core needs replacing Other possibilities: door seal windshield seal
If drainage is plugged under the grille adjacent to windshieldwipers, the water will drain into the floor of the front passenger seating area. Remove the grille and clear the plug. To avoid recurrence of this problem, clear leaves and other materials laying on the grille. Mike
sounds like ya have a heater core leak . time to take her apart
Are you running the air conditioner? If the drain line is plugged, it will leak water (condensation) onto the passenger side floor.
For me it's sound like you have problems with the right door. Check the rubber/palstic parts around the door.
heater core may be leaking or hole in floor
It is probably the heater coil. When it stops working water from the radiator goes back through a hose and when it overfills it emptys into the passenger side floor. You can replace the heater coil or bypass the hoses. Second option will cause heater to stop working.