French happens to be one of the oldest and prestigious tailoring shops in Kolkata. They say they ave been satisfying their customers since pre-independence days. You can get designer ghagras, and suits stitched from here to nail that wedding look. Pick a design from the deluge of catalogues they stock or come with your own. You can also ask them to get embroidery done on the garment.
The making charge of lehengas start at INR 850 while the anarkali suits can be stitched for INR 750, but the price will vary according to the designs. They take at least a week to get done with the stitching.