Hi Can welcome to AO. sorry to hear about your power failure. Have you checked the tech section, lots of help and info there. Hope it's not a huge problem.Alfa GTA & GT - Alfa Romeo Forum
Alfa UK warranty is 2 years plus one year from the retail dealer, which Alfa now sometimes claim is as good as their own. Does this mean you are not UK based, or have a personal import?
Could have lost electrical connection to the fuel pump which is in the tank under the rear seats. If its quiet you should be able to hear when you switch on if the pump is going.