airconditioning

Of course it can be repaired. Might just be a little low on refrigerant. Take it to any shop that services AC and have them look it over for leaks, then top off with refrigerant. You *could* gamble on those throwaway refrigerant refills (cost about 15 to 20 bucks apiece for 1 lb), but if there is a leak you will just be wasting money.

If there is a leak, what does a full repair likely cost?

You can try repairpal for cost estimates, there's too many variables to give a pat answer.