Here is what needs to be done.  You need to remove the fuel pump from the
motor.  Get a torx driver from your FLAPS.  Remove the cold start arm from
the pump (has a clip on it) and use the torx driver to remove the plate
behind the arm on the pump.  Now you will see a small o-ring.  Take it to
local NAPA and get a new o-ring that matches this one.  Put it back together
and it should be good to go.  I did this on my sister's Rabbit a while ago
and it has been fine since.  Sometimes you can put the cold start valve in a
certain position and this will stop it from leaking as well.
Let me know how you make out.

Thanks,
Ken Wilford
http://www.vanagain.com
John 3:16
Office (856)-765-1583
Shop (856)-327-0027
Fax   (856)-327-2242