The only thing I can add to what has been said already is shoot raw and OVER EXPOSE. This goes well beyond the common saying of "expose to the right."

When I shoot indoors at high ISO settings I over expose by half a stop for just about anything but pure white, smooth-coated dogs and really flat black dogs like Belgian shepherds. I go +1/3 and +1 or more for them respectively.

This really helps with digital noise since lightening in post brings out more noise whereas darkening does not. In many cases, one must simply decide what the subject is and blow the rest.

If you can get in close, renting / borrowing an 85 1.4 might be something to consider.