I don't think there is much you can do except go to an official Alfa Romeo dealer, by bus.
If you have the car's 5-digit security code (not the same as the radio code), they can supply a new key with immobiliser chip to match your car, but it won't be cheap. If you don't have the code, you'll have to pay for that on top. You'll need to take ID and the V5C.
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