How do I keep this Salvia Divinorum alive?

I got a plant from my buddy for my birthday since we like to experiment. It get’s pretty cold here at night and at one point there were lice on the leaves. The plant did fine for about a week but when I woke up this morning most of the leaves were hanging as if they had died. The soil should still be pretty rich and I’ve been watering it about 3 days apart.

Decided to take a picture:
http://storenow.net/my/?f=3499