crankshaft position sensor

hi, i have had a search and cannot find anything about my problem:
 
my 1997 a3 has been misfiring. if i am in five gear for example you will feel the car jerk for a few seconds before normal power is restored. if i happen to be in first/second gear, the accelerator does not give any power.
 
my local garage has had a look and the logs on the onboard computer indicate that it needs a new crankshaft position sensor.
this is £108+VAT.
 
(1) Should this fix the problem  and (2) is this a decent price?
 
Thanks...