I run fine with a steady 40 FPS on a GTX 460 I7 quad core (3.8GHz) and 6gig ram, have had almost no issues and no drop's in FPS. (This is at MAX video settings and 1080P resolution)

Would I like a better vid card and 60FPS yes but i can't buy one now. so... now the real question is do you run ANY programs in the background (like the one that monitored your max/min FPS)... im no rocket scientist (though I do work in IT) but that can have a REAL effect on the game, also there are other factors besides poor programming (which I've seen no evidence of poor programming in this game so far). Also how often do you turn off your PC (it does help to power off some times and clear your ram).

I quite agree your rig should handle this game at max settings though solid 60 FPS might not be quite there (but id say no lower than 35-40 by my estimate) as there's more to what happens on your screen than sheer teraflops of proccessing from your GPU

I hope you find a solution this is not meant to belittle your problem! Computers are complex and so are the programs that run them so finding a fix could be hard, keep up the good fight (and talk to your resident IT friend he might be able to help)