If the vehicle was parked in a lock-up of some description, then the garage would be responsible but, since the vehicle was parked on the road - the only way to get recompense is to claim from your own insurance. You must formerly report the theft to the gardai, your insurance company won't pay out otherwise - there is usually a delay in paying out for theft claims of 21 days, (just in case its found) and then the claim will be settled with the book value or the sum insured which ever is the lesser, obviously having proof of a current NCT, receipts for alloys etc can bump up the value. What sort of car was it?