The house my family moved into ca. 1942 had a swamp cooler attached; but it didn't really do much good, so we opened a couple of windows and trashed the thing in the middle of the first full summer.

LiK's mom was satisfied with hers for about 30 years, and it did really help in N. Texas.

A problem with the existing AC might be just that it takes a long time for a small AC to bring the room temp down, so turning it on when you go into the office may not get it comfortable by the time you leave, and if it's a central air setup getting the right vent settings to have "unequal" temps in different places can be difficult.

For around $200 (US) you should be able to get a 6,000 Btu "window unit" and for a little extra get an "apartment sleeve" that you can install below a window (or anywhere else). The sleeve goes through the wall to the outside in a hole approximately the same size as the "front end" of the AC, and you just slide the AC in and plug into an existing (or added) outlet and cool just where the air comes in. (It's usually recommended that you have a separate 20A outlet for the AC, since existing outlets may overload when you add one to them.)

Run the outside condensate to the rose bush and you can forget about watering it, since the AC will run mostly when the rose needs the water. (My dad puzzled an AG department gardner with the birch tree beside the house for years. He made several visits back and never did figure out that it was "drip lubricated" by the AC, and always left muttering "You can't grow a birch tree in the middle of Wichita.)

John