When you take pictures with the flash, it looks unreal because your room is not normally lit by a flash or by only a light source attached to your forehead.

Now, assuming your room is dark but not pitch black, what you need to do it take a photo without the flash. To get better results you will have to:

• Increase your ISO as high as it is acceptable to you. You can go to 1600 or 3200 if you do not intend to make a large print with the image.
• Open your aperture as wide as possible. You do this in A mode and turn the dial until you get a bright aperture (smaller numbers). You will see the shutter-speed increase at the same time if you are doing it right.
• Buy yourself a brighter lens. Something with a wide maximum aperture. A number of not so expensive ones have F/1.8 or F/1.4 (even better). This lets it get 2-4X times more light than the kit lens, depending of the focal-length.

Note that there is always a limit. At one point, it becomes too dark for any camera and lens. If you have people in your room, then the shutter-speed should at least be 1/60 if they are still and probably 1/250 if they are moving. Otherwise they will appear blurry.

Once it becomes too low you can add artificial lighting but you are looking at a heavy and expensive setup to make it look close to natural.