If your going to be trying to smoke J's in your room for more than one occasion I'd reccomend getting a REAL fan to suck the air out the room. And by that I mean a squirrel fan. These things are used when serious ventilation is needed, like glass blowing, kilns, warehouses, grow ops, etc. It will turn over a rooms air volume quick and completely. Here is an example I (quickly) found on ebay...
500 CFM Squirrel Cage Fan - eBay (item 150358681144 end time Jul-19-09 21:59:08 PDT)
I'd make a cardboard cutout to fit your window, make a hole for the exhaust duct on the fan, and smoke away. If the smell can still be smelled, I want some of your nugs!