I've done everything you suggested already,

I bought a docking station yesterday but couldn't find a way to access the disc. Then, by searching the web, I found a solution today, called Ext2fsd, which allows me to read the HDD in the dock from my Windows computer and copy the contents.
I am transferring everything from the remaining drive to my laptop now.
I have also bought two new 1TB drives, doubling my capacity in the NAS and hopefully giving me years of worry free use of my 323. I don't think I will be using the old Maxtor HDD anymore. It's 5 years old, maybe better not to rely on it anymore.
In a few moments the configuration of my new discs should be ready. Hopefully everything works. If not, I'll be back!