do you multibox at all? Even though ffxi isn't known to be a graphic intensive compared to many others, it's still not the same as when it just came out some ten years ago (if you crank up all the settings of course).
I'm currently running gtx 660m on my laptop and with all the lowest settings, i can roughly triple box decently, but you can forget about doing stuff like besieged or wkr when there are lots of people.
it is however a different story if you're only playing 1 character, my suggestion is to look up your current graphics card with benchmark scores, a good place to go for example would be here:
http://www.notebookcheck.net/NVIDIA-GeForce-GTX-660M.71859.0.html (that's for my 660m), go down to the general benchmark scores, ie) 3DMark 11 - Performance GPU 1280x720, and look at the graphics card's benchmark score, and use that as your current standard, and compare it to your new laptop candidates' graphic's card.
for "bang for the buck", i suggest waiting for lenovo y series to go on sales (slickdeals.net?), they *usually* have the best price/performance with a mid-high range card. with the new gtx 9 series that came out, the 8 series are being pushed on sale quite frequently, you can very easily get a laptop with gtx-860m for under 700 bucks which will last you some good time.
these are all opinions of course, but personally i'd go for the best specs you can get with the price you're willing to afford, because laptops aren't like desktops which you can just pull out the graphics card and put a new one in, it's always better to have the better specs even if you dont need it (right now), than to barely support what you can do now but in a couple years you need another one because it's not powerful enough.
hope this helped!