(1) depends on if its rear or front - im assuming its engine oil thats leaking
you actually have three seals in the rear - crank, intermed, and cam - any
one of these can spew oil at an incredible rate if its really shot.
There about $5 each but i think the dealer wants about 8 hours to do 
the job (have your timing belt replaced at the same time
unless its really new) thats about $300 in cortland and $400 in ithaca
(20 minutes away:-)

get them all done - all the labour is in taking the rear of the motor apart
once they have done that its one,two,three.

If its the front seal its  trans-dropper - personally i hate to pay
people to do grunt work like this especially $40/hour!

Unless you know its got less than 20K on it i would replace the clutch disc
and the release bearing (but not the pressure plate or the flywheel) if i had the trans off. (Of course if they show scoring or other damage then replace.)

you can do the trans your self if you have a nice firm floor in a garage to
work on.

oh yeah - i think i have heard of a few people (diesel Vs only?) who
have had trouble with the pilot bearing in the crank seizing up - another
$N part (as opposed to $NN or $NNN ...) which i would replace as a matter of
course.

if you get into w/c idiot book for these seals remember that in the dV
whats referred to in the book as a front seal is in the rear because
your engine is mounted differently. 

sps
Stephen P. Smith
Director, Facility for Laser Spectroscopy
Department of Chemistry
Cornell University
Ithaca NY 14853
607-255-0580
607-255-4137 (fax)