So, you want help regarding what laptop you should look after, or if the game will run on your current one?
Depending on the specs, 2 gb RAM isn't that bad, Civ5 is more CPU dependant rather than anything else.
Vista is a bad OS however and is ineffective (Comparing with 7) as it chews moar RAM. It may leave you with 1,2 gb of RAM free without anything else.
It just means that the game would need to use virtual RAM to function more, but in small maps it might not be needed.
So, regarding your new laptop; first make sure it's a dual core, at least 2 ghz dual core, doesn't matter if its ATI or Intel (Intel are however more expensive). For a video card, you have to choose one that is either ATI or Nvidia, if it's an intel video graphic for mobile you MIGHT have problems, since they're troublemakers.
However for you, if possible for a gaming machine I would recommend a PC computer rather than a laptop, unless neccesary, since PC are way easier to update and repair, that of course if you don't mind sitting in the same place. It's also way much cheaper get a gaming PC than a gaming laptop, but overall, most newer laptops run Civ5 on medium or minimum just fine. Just make sure it's not a bargain laptop and you're set.