From these symptoms I'd say it's probably the crank sensor, though it's impossible to be sure without seeing the car and doing some diagnostics
Dont go to the Vauxhall dealer, they tend to be vey expensive, use an independent.
If it is the crank sensor it's a fairly simple job to fit, no special tools needed, any competent diy mechanic can do it.
As cdc says, ask around for a good garage.
A lot of garages do still overcharge women, at the risk of sounding sexist get a man to take it in or to go with you.
spenny
October 2010