eL.ectron1k,
If you already have stuff on your flash card then use Gparted. You can easily resize partitions and make new ones from empty space. Since ubuntu is stalled, you can try to install debian instead. They are very similar[ubuntu is based on debian], but ubuntu repositories have newer builds. I was somewhat successful following this: https://elektranox.org/website/debian_on_n900.html#nodm guide, but the gnome was unusable because of some bug.