What setting's do you use for Nikon SLR for low light setting?

I have a Nikon D5000 and sometimes when I'm in a restaurant at night where there's low light, and I take a picture it comes out really blurry and It sometimes takes a little longer to take the picture (which makes it blurry)
I have a piano concert to go to soon and I have a feeling that there's going to be low light but I want to have perfect results.
Please tell me the settings of the camera so that it won't be blurry.

Added (1). I'm going to a piano concert to take pictures for the pianist. He hired me to do them.

Well the sensor has to capture a certain level of light through its lens. If there's less light and yes restaurants and concerts are like that then there's less light meaning something gotta give. Either the exposure time goes up [meaning more chance on hand shakies], the ISO has to rise to make the sensor more sensitive [at the price of adding noise] or the lens has to go wider open [of course if your lens only goes wide open up to 5, 6 at 55mm. Then well that is it!

What can you do to improve the situation, well tripod can help it offers a nice steady base for your camera. Of course at concerts those are forbidden and yes at restaurants you are kinda stuck to. At most you might be able to use a gorilla pod. So in many situations this is either hard to get done or not possible.

Raising the ISO well can't fix that the only way to fix that is by effecting the two other factors really.

A wider lens, yup a lens with a wider diafragma is one of the things you can do and is many times done to get decent exposure times in bad situations. For instance there are zoom lenses that do F2, 8 over the full range. And not all cost over $1000, some are as cheap as around $400. I say that is pretty darn cheap!

If you want quicker you need a lens that goes even wider open. That is Primes.ever seen a small body lens with a HUGE piece of glass on the front, that either is a very wide zoom or a Prime. Primes have only one focal length, the composition and framing is done by your legs. This does makes them harder to work with due to possible space issues. Lets be fair it is nice to have a super lens but if you can't get close enough you can't frame the shot well.

Not to mention at concerts and other places the use of a DSLR might just be forbidden. Ya gotta ask about these things you know.

In the shortest of terms even with pro tools it is not easy. And if you got ticklets in a middle or row behind.forget it!

You will need to have a slower shutter speed, larger aperture, and if that does not help, raise the ISO

there are entire books dedicated to your question, I suggest you look into them