I strongly suggest that you acquire a decant from The Perfumed Court before spending $205 USD for 75 MLs of SDV. Some properly regard SDV as the quintessential and most beautifully constructed vanilla dominated fragrance, others of course, disagree. However, some, myself included, feel that SDV wears just a tad too sweet. So please sample before leaping.
After providing it with a few wears, and if you then seek to acquire a full bottle, if there is not a Guerlain boutique in your area, I would suggest contacting Bergdorf Goodman in NYC. Ask for a very nice gentleman by the name of Jason Beers. I believe he is the Guerlain Counter Manager at Bergdorf. In addition, he maintains an e-mail list where he periodically notifies his customers of Bergdorf's Guerlain specials.
The Bergdorf NYC direct line is 1.800.218.4918.TJ