Well, short of washing the heatsink and changing the thermal paste, there isn't much else you can do. I do have another suggestion though. If your card has support for voltage control, try undervolting it a little. Should give around 2-5 degrees lower temperatures. If it doesn't support voltage change via Afterburner, try looking for a custom firmware (but be VERY careful with this. It COULD render your card unusable if you flash the wrong image) for your card with lower voltages. You could also lower the "power limit %" in Afterburner, but that'll also reduce performance.
Needless to say, if you've applied an overclock, please go back to stock clocks.
Also, you said your side fan is an exhaust, try changing that to intake and see if it makes a difference.
And if you have any secondary cards (sound card, wifi card, LAN card) installed near the GPU, move them to a slot that's further away if possible, or just remove those extra cards to check whether they could be causing the higher temperatures by obstructing airflow.
As a stopgap solution, try laying your PC on it's side, and remove the side panel. Check what temps that gives you. If they're better, just keep it like that till winters get here
If you're really concerned about these high temperatures and nothing seems to fix it, try talking to the person you bought it from, and ask them if it'd be possible to have them clean the card without voiding the warranty, or provide you with a new one if possible.
