Oh, I was thinking the empty PCI slot was on the other side of the card (i.e. on the fan side)...a picture tells a thousand words!
Yes, that case is starving your card of fresh air. That being said, it would do the same thing to any video card - at least this one has a fan - a passive card would really be starving for air. And it's quite amazing that this tiny card more or less was the largest card you could possibly fit in there.
Well, I think you just have to run with it. You're enjoying gaming a whole lot more now, and you haven't spent a ton on the hardware. I like to keep HWMonitor running in the background while I game - perhaps you should too, and in a worst case scenario, you could just remove the side panel while gaming. That could make a big difference in this instance, although I applaud Acer for at least including vent holes near the VGA fan itself.