Ways to improve cold air intake?

[NWFSS]

I have a Fiat Seicento Sporting. The current cold air intake is from piping which goes from the filter, through a sensor box (I think), and then straight down. The end of the pipe is open and faces the ground (not forwards).
I was wondering if there were any ways of getting more air into the engine (like a fan or something), or any ways to possibly protect the intake from sucking up water or debris?
The car also makes a terrible wurring noise when I am reversing or stopped, like it is starting to overheat (but I dont see any change in temperature of the engine).

Any help would be appreciated.