I am translating an article «Energetic America» for my exam and need some help.

«If the twin scourges of mankind are sin and ignorance, America's energy problems, according to the political and environmental left, are caused by our sins against nature. In this view, the problem goes all the way up to the Oval Office, which is supposed to be living in sin with the energy industry. If the left is correct, America's energy situation must be hopeless.»

In this paragraph I can't understand what is meant by the word «left». My dictionary says only that «left» is a side (there are left and right sides) and also it has a small sentence that the left is a kind of opposing political forces. Please, clear it up.

«Put in common units, nuclear fuel in 2003 costs about 50 cents per million BTUs (roughly the energy content of nine gallons of gasoline), compared with about 85 cents for coal, $4.90 for natural gas, and $4.50 for crude oil (see chart below).»

Here I would know exactly how native speakers pronounce «$4.90» and «$4.50». As «four-point-ninety-dollars» or «four-dollars-ninety-cents» or in another way?

Thanks