car photography(night),landscapes, animals, and of course my reef
Those are 4 completely different categories requiring 4 different lenses, each easily going over your budget. Animals alone (assuming you aren't talking about a cow 5 feet away) might be closer to $1000.
Car photography would be easy...but night will cost you extra. One option would be to get a nice external flash unit, which again will peg your budget. The D40x scored poor on ISO tests, so depending on the quality of photos you want, you will need an even better lens than other DSLRs for ambient light...ect. ect. I don't want to sound mean, but $200-400 for all that is a pipe dream. I don't think a single lens exists for any price that can do all that.
We could do the reef aspect only and juuuust hit $400 with a 3rd party lens. The Sigma 105mm macro. That does however leave out cars, landscapes, and "animals" (which you would have to be more specific about).
You could get a high quality ultra wide zoom and kill cars and landscapes with one stone. I don't think you can keep it under $400 though.