How to get media from albums.

Hi, I have some video files in my iPad under albums. I can see them when I hit the "photos" icon. When I sink my iPad with my computer via iTunes I Can see the folder "camera roll" and copy items from there, but I cannot see other albums that I have these videos and some photos. Also it is not possible to carry them to the "camera roll" folder. However it was possible to move the pictures that were in the "My photo stream" etc. that was in the "my photostream" to the "camera roll" and I was able to take them (copy them) to my computer.

How can I get these photos/videos that are in different albums?

Thanks ASLI