Putting A/C in an upstairs apartment...?

Question:Hey everyone my name's Andrea. My husband and I live in an upstairs apartment in Orange County - and last summer I about died from heat! Not only does living upstairs make the heat rise, but the sun sets right in our windows! Well, this July I am at the end of my pregnancy - so I *know* I won't be able to handle the heat. We want to put a Window A/C in our slider doors to our balcony because that's the only place it can possibly go - I was thinking we could pull the door shut on it and seal it off with some plywood. The only thing is, I don't know what kind of A/C to buy? Our apartment is about 600-640 sq. ft. Because of the intense heat that locks up in here, should we buy a real strong A/C that covers like 900 sq. ft? If so, what brand is most reliable? I don't want my baby to suffer the heat this summer most of all! Thanks guys!

Answers:
If you are going to have to block your sliding glass door you might want to try something like this. I rent a vacation house and use one of these myself.

http://store.airconditioner-portable.com...

The 12,000 BTUH is a little large but if you have high heat loads (Glass, poor insulation, etc.) you may need that large of a unit.