Final Fantasy XIII-2 has a release window for the US. According to Siliconera the sequel to Final Fantasy XIII will drop in the US, January of 2012. This is roughly a month after the Japanese release of the game.
Only the second Final Fantasy game to get a direct sequel-the first being Final Fantasy X-2-FFXIII-2 promises to address some of the problems people had with the first game.
XIII-2 will feature a more open world which will allow for more exploration, the return of towns, and more action elements such as a jump button and QTE events some which occur mid-battle.
The story is a direct sequel from XIII's so if you didn't enjoy the story of the first game then the second may not change your mind. The story follows Lightning's sister Serah, as well as a new character Noel.