Well OP, I read through this thread and didn't see the best suggestions.
I'd doubt your graphics card would be using noticeably more energy compared to any other card during normal desktop use. The only time it should really consume more energy is when the GPU has to process more intensive stuff such as 3D rendering / gaming.
Anyways, you might want to look into getting a more efficient power supply for your pc. Look for one of those 80%+ efficient or one of those 'silent' type power supplies. If you've got a cheap chinese psu right now, 60 to 70% of the energy it's using might be actually going to use in the components inside your pc. With an 80%+ psu, 80% of the energy pulled from the psu goes to use in the pc.
Secondly, I don't know what kind of monitor you have, but if it's one of those old CRT monitors, you'll want to replace that with an LCD. Again the CRT uses more energy than an LCD, thus generating more heat.
Next, you'll want to be sure your room can cool off once the sun goes down. Check your lighting. If you're using something like one of those standup halogen floodlamps, they use a little 500w bulb. I think most ceiling fans have 4 light bulb sockets in them. If you're using standard 60w incandescent bulbs, that's 240w being used there, with about 220w or so doing nothing but generating heat. Try to replace those bulbs with the compact fluorescent kind. The CFL's use 15w instead of 60w but put out about the same amount of light.
Now I noticed someone here said that the a/c vent in their room didn't really work too well. I had the same problem back when I was living with my parents. Apparently when they bought the house they complained that there wasn't enough a/c going to their bedroom. So the builder changed something with the venting. Now when the thermostat is set to 80 degrees, my room and my brothers rooms 'cools' off to about 84 while my parents room was nearly 75 degrees.
My suggestion to that is to try and build one of those "ghetto a/c" units. Basically you wrap some copper tubing around a fan, and then fill an ice chest with water and frozen water bottles. Then you use a pump to pump the cold water through the tubing around the fan. I haven't built one of these myself but I plan on doing it, and it seems like it would be a great supplement to a hot room.