The Witcher wiki now has a light themed alternative for the wiki skin. To check it out, go to Special:Preferences, then choose the "Appearance" tab and click on the radio button next to "Hydra".
There is only one harpy queen in The Witcher 2: Assassins of Kings. She is found in the harpy lair. She is surrounded by "attendant" Celaeno harpies and can cause bleeding, so beware. Once defeated, she drops a sword named "Harpy".