SpotLight doesn’t index Bootcamp drive, since it has another file system. SpotLight indexes only HFS and HFS+ file systems.
To find files in a Bootcamp drive from Mac OS X drive, do the following:

• Type in Terminal
  
  Default

  $ cd /Volumes

  1	$ cd /Volumes

• Then find all your drive names, you have:
  
  Default

  $ ls

  1

  $ ls

• Now you can search something by pattern. For instance all Microsoft Word files in Bootcamp:
  
  Default

  $ find BOOTCAMP -name "*.doc"

  1	$ find BOOTCAMP -name "*.doc"

• After you have found what you need, you might want to stop the search, that can be pretty long. To stop search just press Ctrl+C

Reference