I tried sending this in a PM but apparently my computer hates me.
There is a lady who makes dresses on the Calle San Luis right below the Helados Bon. I bought two dresses for my daughter at Christmas - gorgeous, poofy dresses with taffeta and satin and ribbons. Princess style dresses. I paid about 1600 for both. She has a few styles and tons of colors to choose from, and you could probably negotiate price, but the most expensive I found was 1200. Her name is Evelin.