We have a different model than you but we did spend a summer in Phoenix a couple of years ago. Wow was it hot! You don't say where you are but it sounds hot. I assume you have just the one AC. You can always add another AC. Many units are prewired for a second unit. Before you go that route make sure you have the AC unit running at the HIGH setting. Also make sure the AC vent at the unit is open. This will dump a lot of cool air right at the AC.... which helps cool things down. Once things are sort of cooled down close the vent at the AC and air will be pushed into the ducts thru out the unit.
If you are getting a lot of direct sun thru the windows perhaps some reflective sunscreens would help. We also got some of the "insulation pillows". We shove these up into the vent openings. We found they really do help. They're also good in the winter to help keep heat in.
But if you are in a very hot area the only real answer is probably the installation of a second unit.
Good luck and stay cool..... Oh, yeah.... remember the unit does have wheels and you can always move to the mountains or the ocean.... hopefully it would be cooler there.