Tent getting hot with Air Cooled HPS

Hi Guys,
 
Just setup my grow tent after not been growing for a while, i had been using some LED's Previously but decided to get some air cooled hoods 600W due to the low yields from the LED's.
 
i setup my dr240 1.2 x 2.4 x 2.0 and vent system like this
filter--fan--hood--hood--extract to window
 
i did not use a fan to push cooler air in the tent and as a result it hit over 100F in a few hours!
 
so......i changed it to ......
filter--fan--extract to window   and the hoods air cooled seperately....
6" fan--hood--hood--extract to window
 
this setup saw my temps hover around 91F!!
 
the room my dr240 is in is 3mx3mx2.4m....it is a top floor flat with an attic space above...i was thinking of venting the warm air from the hoods into the attic space and the filtered air from within my grow area through the window.
 
i know not to vent the filtered air into the attic due to moisture from the plants and mold can be a problem if i did this, that is why i was just thinking of venting clean fresh warm air from the lights to the attic instead.
 
my room temp without any lights on is around 75F so if i could expel the warm air from the lights into a different area that would help to pull some fresh outside air into the room where my tent is located.
 
i am tempted to try this setup....
filter--fan--hood--hood--extract to window
6"fan pushing air into my tent rather than just relying on the box fan to do all the work.  i do have a twin fan speed control and am aware the tent needs to stay on a negative pressure.
 
I absolutly cannot have the hoods under a negative pressure due to the air leaks in them, they are not top dollar hoods and i will not take a chance that smell will start to seep through them 4-5 weeks into flower.
 
does anybody have any ideas or advice on what to do in this situation, 90F is too warm and smells start to creep through filters at this temp!!
 
reagrds
Steveo