Well ideally you would want the filter horizontal hanging from the roof to suck up all that hot air and humidity and smellls.
Best option is to attach your fan directly to the filter, have your fan Sucking on the filter, then run your exhaust to wherever you dump the air. Also, once everything is attached get some duct tape and tape over anywhere where it might leak, go nuts its worth it.
If your really trying to keep odors from going out the door, you might want to build a small "Air Lock" out of poly. You can even get poly zippers that stick to a sheet, then you unzip it and cut the inside to make a door.
Also What kind of fan are you using? Im not sure but it sounds that might be your problem?
Centrifugal fans will give you the best power and you wont lose as much pressure or power, this also depends on the type of filter.
