how good is my computer?

[Xuvial]

I will say the one time I bought a super cutting edge card ($399)

Was it a 8800GTX?

[BicycleMafioso]

What resolution do you play in?
People should remember to ask that.
A card that's lagging behind in 1920x1080 could very well be capable of pulling its weight in 1680x1050 or in 1280x720/1366x768.

The CPU is more than fine. A bit of overclocking could give you a more decent boost than just buying another mobo/CPU and leaving it at stock-settings. And cheaper, too. I'd always recommend a good heatsink, even for non-overclockers. The noise-reduction is a god-send. A Coolermaster Hyper 212 plus with two aftermarket (Scythe Gentle Typhoon 1850/1450RPM) fans with PWM, for example. With overclocking, it's a given.
Yes, the CPU ain't the best, but to be honest, I see no reason to buy a new CPU in just the following generation. 1156->1155, I wouldn't see the point. I'd rather save up til the next generation, as you'd actually not be having enough troubles with your 1156 at this current time to be worth the money. Upgrading would get you better, but not worth the money.

The GPU and HDD, depending on your resolution, might be what's holding you back. Getting a GTX 560Ti would be a good idea, or a HD6870.