You can use Gparted live cd:
http://gparted.sourceforge.net/livecd.phpThen take a look at this:
http://gparted.sourceforge.net/display-doc.php?name=help-manual#gparted-resize-partitionSo ang gagawin nyan eh eh boot into live cd, hanapin mo yung lv na ire-resize, resize it then reboot. Take note na kailangan hindi naka-mount yung partition/lv. Then after mong ma-resize, you can either boot into your system and add new partitions/lv. Or pwede mo pa ring gawin sa gparted.
Depende na sa gusto mo yan. Gusto mo bang may separate partition kada Volume Group (VG)? Or separate Logical Volume (LV) within a partition? Looking at your filesystem, may 3 kang partition. 1 for swap, 1 for /boot and one for the mint--vg volume group.
Dun sa mint--vg VG mo, andun ang root LV mo na naka-mount naman as / . Now, may dalawang option ka. Pwede mong ire-size lang ang root LV and then add separate LVs para sa kung ano mang purpose mo (separate LVs for /home, /var). Warning lang, if you decided to have separate LVs for /var and /home, marami-rami kang gagawin (permissions, moving contents etc.)
The second option, which is mas madugo, he he he, is to resize the mint--vg VG and root LV then make room for new unformatted partition. You will have to spend more time sa GParted live CD. I'm not familiar with how Mint does it, pero most distros have a rescue mode na pwedeng yun ang gamitin mo in doing the resize/repartition.
As always, back up your important data, he he he. I would prefer na fresh re-install na lang para simple. Pero if you're exploring. Try the method above. Order some pizza and enjoy Linux!