Audi 5000 problem

[tombin at idle.curiosity.org]

This evening (after driving my car around all day with no problems), I get 
into the car after work to drive home.  I get about 100 feet from work to 
the first stop light and the clutch sinks to the floor.  Now, I just had 
the master and slave clutch cyl. replaced last summer.  So, I figured 
maybe it was due to the tempature (about 19 degrees outside) but to no 
avail the pedal did not return.  Is there anything else that can cause 
this?  What kind of money am I looking at for a repair?  Any answers are 
appreciated!