" So would you guys recommend me maybe just try to pick up another gtx 660 ti for SLI then since it will be cheaper?"
no, man just wait till the game comes out and if you are getting shit performance on your 660 ti (which i highly doubt you will) you can make the decision then when all the hardware will be cheaper. not to mention bf4 comes out in november if i am not mistaken. run the game on your 660 ti and if you find that you really need an upgrade wait for the month or so until christmas and then get the gpu upgrade at a boxing sale.
furthermore i would venture to make a guess that, given that your other hardware is up to it, your 660 ti will be able to run any next gen game at about the same level of graphical quality as the new consoles will. i am basing this on the fact that a 660ti is simply much more powerful than the hardware in the ps4/xbone. the only way this would not work out is if the difference in the design of the consoles hardware would mean the games are simply not optimized for your setup. the consoles are amd biased with more less powerful cpu cores, lots of what for a pc would be vram - current gpus usually max out at 2-4gb while the ps4 has 8 potentially. all this would mean than a low end amd cpu with more weak cores and a less powerful gpu with more vram say 6gb, could, because of consoles optimization, outperform a 660ti rig. that said a 660 ti is still a beast and should run anything over the next 2 years at max settings.
basically, wait