Must have missed something

I have to move 50gig (9500 files) from windows XP share to debian.
I have 60gig left on my hard disk.
I use gnome file manager to copy the files.
I reboot when 30 gig is copied. How can i resume copying files?

* If i want to copy the whole 50gig again (select all folders), it says "not enough space left". No other options available.

* When i copy a folder it says folder exists, but it doesn't check if files are missing within the folder.

So how can i copy a folder, compare files, and copy when it is not there, else skip the file.

Now i deleted the 30gig and started copying all over again. Takes around 3 hours to copy.

Any pointers, thx.