I made nice shot with my camera but had some problem with focus and the video is a little blurry. Is there any good node setups for fix it? Moreover i have some night shots, which have quite bad quality, what can I do to get a nice quality, when sharpen node produce only grain?
Noise is one thing, focus is another!
There are free and commercial solutions to sort noise - some poor, some fairly good. I use NEAT Video for low-light compensation but day-for-night is a better solution for video work unless you have a great camera. You can reduce noise using a blur in the Blender compositor but it looks as bad or worse than the noise you're trying to mask usually. Natron, a free node based compositor has some noise reduction nodes.
Adobe demonstrated blur correction for stills some years ago but I don't believe this has filtered into video yet and it's not available in Blender. New cameras (lightfield) can refocus after the fact but again, this doesn't help you.
Honestly, if the shot isn't right in camera, you shouldn't rely on fixing it later in post. This is something we hear a lot and take it from another old pro, it always ends in tears! You can't make a silk purse from a pig's ear. I've made (and tried to fix in post) more mistakes than Ed Wood, so I know how this works. :)
Do what the pros do: reshoot it or cut the scene if you can. Put it down to experience and learn from it. As GiantCowFilms notes, the developer who could fix that problem would never have to work again.
You've taken the first step in recognising the shot isn't good enough. The next one is learning how to dump it in the trash! It's hard... I know.