Minecraft Worlds File

Bluestacks is an Android emulator. I'm not sure if it will help you, but maybe the folder path for Android may help. Try navigating to this folder path inside Bluestacks (try installing an app like ES File Explorer):

/sdcard/games/com.mojang/minecraftWorlds

From there, each folder is one of your worlds. They will have a scrambled name. Enter each folder, look for levelname.txt and open it, and you'll see the name of the world. You'll want to get the entire folder.

To move it from BlueStacks to Windows, I think this question may help you. The latest versions of Bluestacks have a shared folder at /sdcard/windows/BstSharedFolder which you can copy the world folder to. Then you can access the shared folder from your PC at <BLUESTACKS_DATA>/UserData/SharedFolder.