Save the photo to the camera roll and you can add it to any album that you create on the iPad. After you save the photo to the camera roll, you can delete it from the Photo Stream.
Tap on the Photo Stream in the photos app. Tap on the photo that you want to save, tap the action icon in the lower Left corner - the square icon with the up pointing arrow - tap on Save to Camera Roll. After you save the photo to the camera roll, you can select it in the photos stream again, and then tap the trash can icon to delete it from the Photo Stream.