Problem with leaky fuel metering distibutor

[Bruce G Plante <Bruce.G.Plante-1@tc.umn.edu>]

I am the original owner of a 1987 Audi 5000SQ with 115K miles and 2.3liter
fuel injected engine.  I have developed a leak in the sensor coming from the
fuel metering distibutor located next to the air cleaner element.  Fuel
squirts and drips on the interior of the engine compartment.  The dealer
claims that the whole distributor needs to be replaced to the tune of $1,300.  

I was wondering:
1)What is the sensor coming from the fuel distibutor?
2)Can't the sensor just be replaced? 
3)Is this a job for a do it yourselfer, local garage, dealer?
4)What should I pay for this? 

Thank you,
Bruce Plante
Minneapolis, Minnesota