How to use a fast shutter speed in a dark room?

Whenever I have a fast shutter speed on (and large aperture too, like 4.8), my images come out dark. Is there any way to change that (other than larger aperture)? If so, how? Btw: I have a Nikon D3000.

A longer exposure, cameras need light

There's not enough light. You can do one or more of the following:

-Open your aperture wider. 4.8 isn't particularly wide. If you got a 50mm f/1.8 for example, you could let in nearly 8 times more light. This is the recommended approach. Buy a fast prime lens.
-Raise your ISO setting. On the D3000, this is not recommended, as its CCD sensor doesn't do well at high ISO settings-it generates a lot more noise than a CMOS sensor, which most DSLRs use.
-Add more light. You could use a flash, a flashlight, a studio strobe, a bright LED, whatever.

F 4.8 is actually not that "large".

This was taken at f 2.8 (largest for this lens), at 1/30 of a second. However, you realize the ISO is 12, 800 and the original had to be cleaned up (it was noisy).

This was taken with even a faster lens, at f 1.2. Shutter speed was 1/15 of a second. The ISO for this film was only 400.

Set the ISO to like HI 2. OTHER THAN THAT JUST SLOW DOWN THE SHUTTER SPEED