Well, I can see from the looks of it your GPU is not a gaming one but one more designed for other media. I've not looked at the particular card, but judging from the name info you gave, it looks like a card not designed for gaming.
I had the same problem when I bought a GT 430 and it was utterly shite, because it simply wasn't a gaming card, unbeknownst to me, although I should've researched it, TBH.
Just looked it up, and my suspicions were half-correct; appears to be a very low-end gaming card. You'll want to upgrade your GPU! It's worth it.
Your CPU is kick-ass, though; same as mine.
Meanwhile, make sure you're using the latest GPU drivers, and if that still is giving terrible performance, then give an older driver a go; sometimes trial and error with drivers can reveal performance boosts.
OK, just thinking that 8-10FPS when it was substantially faster, is atrocious and unusual, so the only thing that comes to mind is a GPU update (from Automatic Updates, for example) has enabled some new fancy features and thus slowed you down; I had this problem with the GT 430 I mentioned, although that was just crap for games, period. You can give OCing the GPU a go, but I'm not sure if that'll yield much improvement. Has WoW been updated since you were getting 20FPS? Reason I ask, is because they might've improved various graphic features. That's me out of ideas, ATM.
OK, thought I'd recommend a card... if you're absolutely restricted by cash, then my brother recently got a card that has blown me away; it's pretty damn good and cheap considering what he gets.. it's the Radeon HD5750; I'd say it's mid-rangeish card. If you're looking for something with a little more oomph, there's what I've got, the PNY 550Ti which is £100 on Amazon (give or take a few quid) which nails most games on max. If you're looking to go a step further, there's the MSI Twin Frozr II 560Ti OC. Finally, if you're looking to get something supreme without going overboard, there's the 570/580 which I hear is pretty "legit". I'm more knowledgeable on nVidia cards, hence the lack of AMD mentioned.