How far are you willing to go and how much do you want to spend? Kleinfeld actually does carry plus size samples if you are willing to take a trip to NY.
Here is a link that has a list of stores that specialize in plus size gowns:
Are you willing to hop on a train and head down to DC? I have heard amazing things about curvy girls bridal.
I will say though... if you are a size 30 in street clothes, you may have some issues buying a gown, unless you get a ball gown or A-line. My suggestion is either travel to one of those stores, or call your local Alfred Angelo signature store. AA goes up to 32w in most dresses. That will be a 28-30 street size. Just ask them if they have any of those samples in the store.
Also, keep in mind, for trying dresses on, you will likely fit into a 24-26 in samples. They just won't close in the back... but unless it's a mermaid, you'll still be able to try them on.
Websites/blogs where our wedding has been featured: