Not enough disk space to update

[msck9@mizzou.edu]

Dear all,
 I want to update the system. I am using "synaptic package manager", and
 choosing smart update. I need 600Mb space to download all the files,
 but I don't have so much space under "/". I think all the download
 files will be in the /var/cache/apt/archives which is under "/". I have
 plenty of space under other partition. Is it possible that I can
 download the files to other place? Or maybe you can give me some other
 good choice to update the system.

 Thanks in advance.
 Ming