Copy from Mac hard drive

Hello,

I am posting this out of desperation :p

Right, i have a Macbook; there has been an issue with the hard drive, which i've rectified by replacing the old HD with a new one. I did not have backups of my data, i tried to recover these via disk utility, however that did not work. I also placed the hard drive into one of those sata enclosure thingy, but the hard drive does not appear on my desktop. I do see it in disk utility, but i am unable to mount it :(

Now, onto ubunto,

I have the 11.04 version. I've followed the directions from this video to gain access to my files, however i am doing something wrong, somewhere.
https://www.youtube.com/watch?v=eMyR...9beLSQ&index=2

When i open terminal, i get the following message 'To run command administrator (user "root"), use "sudo <command>". See main sudo_root" for details. ????? What command should i use? I type gksudo nautilus, then click onto mackintosh HD, users, Elizabeth, then permissions. Owner 503 - user 503, click root, message appears ' Sorry, could not change the owner: Read only file system'. What am i doing wrong? I cannot drag the folder onto desktop either, as it is 'read only'. Help, this is so frustrating, i can see the contents of my folders, but i unable to save onto my external HD :(

Hope all that makes sense xD :)

Edit: The HD is in a external enclosure, i boot from windows into ubunto.

Thanks in advance,

Elizabeth