I'm in the same boat (check my current thread) but at least it seems there is light at the end of the tunnel.
Mine suddenly died late one night, almost a month ago, on a dual carriageway.
Had it towed to my garage; he's normally s**t hot but was unable to trace the fault.
Then it went off to an auto-electrician who after almost a week, threw in the towel, but suspected the immobiliser module.
It was then towed to the nearest Fiat dealer (They service Alfa too) who have diagnosed the immobiliser to indeed be faulty.
After installing and programming the new module, I should have her back by the end of the week!
I still don't know how much all of the above is going to cost... Tiny Tim may have to go without his plum duff this Christmas!
"Looking through the knothole in Granny's wooden leg"