Kris,
  Obviously you must first determine which hydraulic fluid line has the
problem.  The best and most simple way to determine that is to take the caps
off the fluids until you find the one that is low/gone.  If it is brake
fluid you must tow the car until the line is replaced and the air is bled
from the lines.  If it is power steering, you can get by without the fluid
for a very short time before you are going to replace the steering rack.  If
it is water/coolant  stop and do not drive.  If it is power assist (green
fluid) than you can drive the car for a bit before you take care of the
problem.

If it is between the wheels, chances are it is the high pressure hose to the
power steering.  It is a common malady for these to go since they are
stressed by the heat of the engine.

IF you are uncertain as to what you are dealing, I suggest you have some one
with more experience look at the car. Usually there is a puddle under the
car and you can tell what it is by color and odor.

Cheers
Webserve