The problem is that people falsely assume that getting a new generation GPU/CPU will give them a significant boost. Truth is, if they stay in the same range (low/mid/high), the differences will be quite minor, especially with hardware not making that many jumps lately. An example: I'm still using my 260GTX, and for most MMOs it's still enough to run them at least at 30 fps maxed, with some dips in crowded areas. As for CPU limitations, my old Phenom II X4 still has to encounter a game that maxed it out. My brother uses a similar system, but has a core quad instead of a phenom and his GPU is not factory overclocked. There is no difference in performance between our setups except for me having a SSD.

ARR might be a bit more demanding than an average mmo, but surely not as bad as 1.0 was, I hope. The benchmark is around the corner, so is the beta so imho you should waited till then before upgrading.