I'm not familiar with Olympus but I have a digital Nikon SLR and here are some options I would consider:

1) ASA setting ("film" speed) - increase to somewhere in the area of 1000. Will tend to produce somewhat grainy photo's.
2) Flash - Probably would need an external unit as they provide more light.
3) External lighting - Most better digital cameras can adjust for color temperature. For example if using incandescent light, the camera can adjust. Also, most photo finishing software can do this too.
4) Tripod will allow longer shutter speeds and lower ASA setting for better quality photos.