Where in Southern California can i find stores that sellauthentic traditional peruvian costumes for a 7yr old?

my littlle niece is participating in a tv competetion "nuestra belleza juvenil" and her challenge is to represent the country of Peru. Who ever displays the most unique peruvian costume will be the winner... i dont know where to shop for latin america traditional dresses or folkloric.... i live in los angeles, if any one can help me find stores or shops .......your help is highly appreciated..... she's really enjoying this activity & is so entusiastic in winning...