Bridesmaid dresses

Hi!!!!
I am going to start looking for bridesmaid dresses and I was wondering if you could tell me who has the best selection- I am not set on any designer but I do like Bill Levkoff alot.

Any suggestions would be great!!!
Also, I am willing to travel but are there any great stores in nassau County????

Also, if my wedding is in October- when should I have the girls dresses ordered by??

TIA!!!!