Lighting for HD video in a dark room

I want to start recording a weekly lecture series in HD, but the current lighting setup doesn't allow it. I'm looking for some inexpensive lighting that will help me film it. I don't need the best possible quality image, but something that looks decent would be nice. Anything would be a step up from the current conditions, which essentially would produce unusable footage.

The 2 hour long lectures happen in a large room with a 13" high suspended ceiling with fluorescent tube lighting, and the left side has large windows with blinds all the way down. The lecturer typically stands near the front of the room, about 8 feet from the windows, but the front three rows of lights where he stands are turned off so that the projector screen is visible. This makes the subject quite dark, and thus difficult to film. The other thing to keep in mind is that the lectures happen in the evening, and as the days get longer, there will be more daylight in the room. It will start to get dark outside part way through the lecture.

I'm a newbie as far as lighting goes, and feel overwhelmed when I try to browse for products. Can anybody suggest where I should start? I want to avoid blinding the lecturer with a direct light in his face. Something ceiling mounted would be ideal, but I can go with something on stands as well. We will eventually look at replacing the projector with a high ANSI one that can produce acceptable brightness and contrast with the rooms lights on, but that might not happen for a while.