Theoretically you may have some legal leverage against your landlord. I don't know what the law is like up there but down here in florida if your landlord refuses to let you get decent air conditioning you've got a good case against the bastard.
That aside I would suggest getting some good quality window air conditioners and then hacking together a stand, drainage pipe, and some kind of airtight seal connecting it to the window. It should (again, theoretically) function just as though it were sitting in the window normally.
I think there are also units out there that are designed for use with barred windows and have a really small hanging bit.
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And evaporative coolers suck. You're basically harnessing the awe inspiring power of a bucket of water and a fan. You'll also be getting a solid 80-90% humidity in your apartment if you go with that. Not only is it uncomfortable as hell but it's going to make dealing with mold a bitch. You're also going to get condensation all over anything lower than ambient temperature which, given the nature of the system, will be just about everything you do NOT want having water condense on it. The motherboard I had before this one died partially due to heat death and partially because of condensation frying it.
It's a really nice concept, and it works decently for some industrial applications, but there are just too many risks and downsides for it to be useable for any place you want to live in. Put it this way: I live in an apartment that basically has no AC at all during the day, in orlando, and we're going to wait for the right AC system to arrive rather than deal with evaps.