Re: What wrongs with my built?
If it's a quality PSU, it's probably sufficient, since it's not a power-hungry card, and your gear seems good enough; looks like your gear is quite good, contrary to what the other person said; just because something isn't the latest most expensive thing, doesn't mean it's not high performance. For the resolution you're at, I would've expected (from looking at benchmarks of a lesser version of your card) you to have much better performance than that.
Your card should handle Metro 2033 at 1920x1200 resolution with 16x AF, AAA, and all other settings maxed, at 18.8FPS. (obviously allow for wiggle-room, since the system used to get these results was probably higher-end)
Try updating your GPU and motherboard drivers, if you haven't done so already. The only things I can think of, is faulty gear, or something awry in the OS. The info' is too vague for me to give a better suggestion.
I think the PSU is a German brand, and when I Googled it, I only noticed it on a German site, so I really know nothing about this PSU, which questions the quality, perhaps. I would look into whether it's a decent PSU or not. NEVER go for a really cheap PSU, if you can help it. I recommend Corsair, but they don't come cheap; others tend to recommend OCZ.