aye, its svcky but really, id rather get the gpu/monitor now, and replace the mobo later. get some use out of it you know?
and I totally get that, I think that's the better move anyways. In your position I'd much rather get a 6970 mixed with an AMD 3.2 that can still be OC'ed, vs a sandybridge 2500K with some cheap motherboard and still stuck with a midrange gaming card from two years ago.
ED: I think Starforce's post a few up from here referencing how he was using a 6970 to drive his triple screen setup is sheer proof of ability enough of that card's abilities. That's 5760x1080 of pixels and it was cool with that, compared to how your GTX460 is struggling to pull off 1600x900. Dooo it

Oh and remember that with the 2GB of faster vram means texture packs are a non-issue for you. Iike as an example I tried unloading the two dozen or so HD packs I'm using and no joke the FPS didn't change a single point, nothing, they just don't bother modern cards with those sorts of abilities.