I have the Panasonic f/1.7 and an Oly kit 14-42mm. The Panasonic is a terrific piece of glass. The oly is OK.
Here's the thing about low-light photography. If you're taking pictures of people, a wide aperture lens is a good thing. When you use a wide aperture, you necessarily get a shallow depth of field. So, you'll get your person's face sharp with some nice bokeh in the background if you focus accurately, and you'll have a short enough exposure to avoid motion blur.
If you're taking landscape pictures without foreground subjects either lens will do the job. The same is true if you're taking landscapes with foreground stuff -- the advantage of the f/1.7 melts away because you will have to stop it down to get the depth of field you want. In that case, spend your money, as somebody else suggested, on a tripod so you can hold your kit steady as you're taking a long exposure.
By the way, you need to learn to use the G2 in aperture-priority mode to control all this well enough to benefit from such a wide lens.
All that being said if you can afford the Pana f/1.7 you'll like it.