374 MB just isn't that much for OS & stuff. My root partition has 640 MB used and I'm not even trying to fill it up. I think that you're up for a repartitioning. You can probably copy the files from your system partition and return them after the partitioning, but I don't know the details.

I suggest creating a large root partition and a small "internal card". Everything you store on your /home/user -directory is saved on the root partition so you can utilise it quite well. The "internal card" is there mainly for compatibility.