Clothes And Bras For Large Bust?

I am a 36DD, and I have an extremely difficult time finding clothes and bras that fit well. Really, the only thing I have right now is the Nakeds Demi bra by Victoria's Secret in a few different colors. What makes things harder I that I am 20 years old. I am picky, and I don't want to wear bras that are ugly, or that look like they were made for old ladies. I want to feel beautiful and feel good about myself, like any woman. Do you know of any online stores or any specialty stores in Westchester, NY where I could find a bra or shirts that fit?