Which lens/settings to use for taking photos of bars restaurants, clubs?

Hi
i want to take some photos of clubs restaurants, bars. I want for example to take a photo off one side of a restaurant and everything on that side will be in photo.
Do i need any specific lens(i already have 18-55 and 55-200 mm lens with my nikon d3100)
or do i need to change my settings)

There are multiple issues here, most bars don't allow photography when the bar is open, some of their clients may be there with someone they shouldn't be, the last thing they want is a photograph to preserve the event.

But I think you mean the low light problem. Low light photography is a test both for the camera and the photographer.

You won't want your telephoto lens will you? So your 18 - 55mm lens.

Set your camera to Aperture Priority (A or Av on your function dial), set your Aperture as wide as you can (lowest f number), set ISO low to start with, half press the shutter button and the camera will tell you how long the Shutter Speed needs to be to get a decent exposure, don't be surprised if it's several seconds in a low light bar. With the Shutter Speed this slow you will get movement blur.

If the bar is closed there's no problem with digital, you just put the camera on a tripod to eliminate camera shake and let it expose for as long as it needs and you will get a perfectly exposed shot. If there are people they will have to stay perfectly still during this time. Not much use when the bar is open.

You only have two choices to get the Shutter Speed faster, increase ISO and accept the inevitable noise or input some light into the scene by using flash or both.

Flash is a whole new learning curve. But it can cure the problem.