GH3 and high ISO - Push it in camera or in Lightroom?

I have a new GH3 and I love it.  I do a lot of very low light photography of moving dancers.  I shoot in RAW and I like use my Pani 20mm f1.7 lens because it has the best angle of view and widest aperture of the lenses in my kit.  However, I have found that even at ISO 6400, I don't have enough light to shoot at the shutter speed I need for the subject.  (I really can't lower my shutter speed below about 1/50 because the movement of the dancers.)

My question is this:  Is it better to increase the ISO in the camera to 12800 or to push the ISO 6400 exposures a stop in Lightroom?

The noise is pretty prevalent in either case and I do employ Lightroom's noise reduction capability to improve things a bit but can't use a Luminance value beyond about 25 without it getting too soft.