It's very underexposed. Check the histogram on your camera - do not trust the screen as they usually give a false impression. You'll see the gap in the histogram (on the right). This indicates there's no white pixels - in fact the brightest pixels are a mid grey. If it's dark, let more light in - open the aperture more, increase the ISO or lengthen the shutter speed. If too bright do the opposite.
But with some editing on your PC you can restore the image however it would look even better if you got it right first and would save time later.
Note the histogram shows pixels that range from black (on the left) to white (on the right).
If you need more info on exposure look at the Understanding Exposure book by Bryan Petersen which is very informative and will help with understanding your camera more and if you need more info on understanding how to read a histogram look here.
Don't rely on photoshop though. Get it right in-camera first. Shoot and then look atthe histogram on the camera and learn how to read it as different scenes will have different characteristics.