well if you are bringing IN warm air, your total heat load is going to be quite a lot and what you should do is put an ac in that window. I mean, seriously you want to be in the high 70s and adding heat to air that is already a little warmer than you want, thats no good.
Once you fix that you should not have to really worry too much about humidity, just keep your plants properly watered.
Fo comparison, my flower room is 1400w and intakes from an air conditioned room inside my house. The exhaust is a 6" duct run through the hood of my 1000w and exhausted to yet a third room. the 400 is not cooled. Bringing IN air that enters at about 65 degrees, using an active boosted intake, things stay nice and happy even though the duct booster fan i have is a peice of shit that can't pull much air at all.