Try contacting clothing retailers and manufacturers in Mexico directly. Ask them about making purchases from your location. Ask them about shipping the products to you.
You can easily get clothing from Mexico in a number of ways. One way is to travel there yourself and bring the clothing back. Another way is to find a distributor online and order from them.
Clothing from Mexico can be located on the internet and then narrowed down to local stores if the stores have a website. If there is a mexican population, there may be areas to go locally that specialize in these clothes.