Have to admit I really don't like pusher fans. To me it always seem like you are in fact impeding airflow by putting something in front of the radiator.
Even if your fan is more than 3/4" away from the radiator, it should still be relatively simple with some thin aluminum from one of the home improvement stores to make your own shroud and assemble it with a poprivet gun. All you're trying to do is direct the airflow towards the fan.
Or you could visit an a/c shop that makes ductwork and ask them to fab something up for you.
