Where can I buy carrera sungles?

The other day my friend left her carrera sungles at my house by accident, i wore them to the beach and I broke them. I see her tomorrow and I want to have a new pair for her. However I dont know where to buy them, I live in the miami/ft.lauderdale area. I would prefer to buy them in person so i can have them when i see her and i can have a gift receipt just incase she wants a different pair but i will settle for buying them online if thats my only option. Basically, the little rubber black part that goes behind ur ear slipt off the sungles and got lost. Although, when i play with he rubber part on the other side of the sungles it easily slips off with no resistance so im thinking that its supposed to be able to come off. Is there any ways I can just order the black rubber part?