The Namco Bandai Games Online Store now offers system specifications for the Windows edition of Dark Souls II that's expected next month (thanks IncGamers.com). Here they are:

Minimum:
OS: Windows XP SP3, Windows Vista SP2, Windows 7 SP1, Windows 8
Processor: AMD® Phenom II™ X2 555 3.2Ghz or Intel® Pentium Core ™ 2 Duo E8500 3.17Ghz
Memory: 2 GB RAM
Graphics: NVIDIA® GeForce® 9600GT, ATI Radeon™ HD 5870
Hard Drive: 8 GB available space
Sound Card: Compatible with DirectX 9.0c or higher
Network: Internet connection required for online play and product activation

Recommended:
OS: Windows 7 SP1
Processor: Intel® CoreTM i3 2100 3.10GHz or AMD® A8 3870K 3.0GHz
Memory: 4 GB RAM
Graphics: NVIDIA® GeForce® GTX 465 or higher, ATI Radeon™ HD 6870 or higher
Hard Drive: 8 GB available space
Sound Card: Compatible with DirectX 9.0c or higher
Network: Internet connection required for online play and product Activation