Wow, lot of stuff to talk about here.
1. If apt is not seeing anything new, then you may not have the repos set up right. Fedora has places you can go to download premade repo settings and setup scripts, perhaps those exist for ubuntu?
2. Smart is a better package manager than synaptic. It can do both yum and apt, expanding your package options. Check it out.
3. The way piratepenguin has suggested you change permissions on your drive works, but it is not the most correct way to do it. The most correct way would be to create a new user group, and allow this new group access. Tutorial at
http://www.userlocal.com/tips/fatmounting.php , should be readily adaptable to ubuntu and ntfs.
4. I learned a new technique the other day. At the prompt type:
su -
enter your password, and then press enter.
Now you can launch apps from the command line as root, without causing the system to freak out. For instance, you could run 'gedit /etc/fstab' and be able to save your changes. Normally, simply doing 'su' alone with this command will cause a lot of memory leaks and maybe even some minor subsystem crashes. This might help you do whatever you need to do as root to nautilus.