You can get it at any of the following links for the Limited Edition. They have their own advantages according to your region and preferences, I think.
CDJapan: http://www.cdjapan.co.jp/detailview.html?KEY=MFBM-1 --> Normal price, but has some price cuts and bonuses you can use if you want to buy from CDJapan again
YesAsia: http://www.yesasia.com/global/hetalia-axis-powers-movie-paint-it-white-premium-edition-matsuri-dvd/1023628367-0-0-0-en/info.html --> Higher price, but free international shipping
no subject
Amiami: http://www.amiami.jp/shop/?set=english&vgForm=ProductInfo&sku=MED-DVD2-09242&template=default/product/e_display.html --> Lower price
CDJapan: http://www.cdjapan.co.jp/detailview.html?KEY=MFBM-1 --> Normal price, but has some price cuts and bonuses you can use if you want to buy from CDJapan again
YesAsia: http://www.yesasia.com/global/hetalia-axis-powers-movie-paint-it-white-premium-edition-matsuri-dvd/1023628367-0-0-0-en/info.html --> Higher price, but free international shipping
Hope this helps! ^^