Good glass is most important. The K-7 has an excellent AF incl. in low light. Some good quality large aperture lens(es) will make more differences than a newer, untested camera.
As an example, I have a Voigtlander Nokton 58mm f1.4 to complement my DA18-250mm f3.5-6.3 in low light conditions. The Nokton 58mm f1.4 is a fast prime lens with a much large aperture than the DA18-250mm.
* Last month, I shot some breaking waves on the coast at sunset. After 19:15, it became too dark for the DA18-250mm for any good quality shots, and the shots taken with the K-7+DA18-250 after 19:20 were unuseable, even at ISO 6400.
* On the other hand, I was able to use my Nokton 58mm f1.4 until 20:00 when it was almost pitch black. Until 19:50 I was shooting at ISO 400 or less, in conditions where the K-7 is excellent. The lens was in A mode and my K-7 camera was in P mode.
What a difference ! A good quality fast lens (ie a low f value) can give you some excellent low light shots with the K-7 both indoor and outdoor.