before you do anything rash, try it out with your current setup and see how it goes.
I think your processor at least should be able to handle it. It's a quad core, 2 cores for wow and 2 for fraps (does fraps even use 2?) I know that when I was recording wow a few years back on my then brand-new quad core, I barely noticed an fps drop from recording. As for upgrading your video card, you can always do that tomorrow.
run the game and see how it goes, if it doesn't perform well enough it's probably your graphics card. If the game plays fine but you get a big performance drop when recording, it's definitely not the GPU because the GPU doesn't do anything for fraps, fraps merely takes the data that is outputted to the monitor and stores it on disk.