On the Ageod web the official WW1 requeriments are
Required system :
* OS : Windows XP/Vista - DirectX 9.0c or more
* Processor : Pentium® IV 1800+ MHz
* 3 Gb free on hard disk
* 2 Gb RAM
* Video card : 128 Mb
* DirectX 9.0c compatible sound card
* Screen resolution : 1024 x 768 or more
So... you will have to get more RAM... and me too!
Luckily, RAM is cheap nowadays. I have been looking around and i can get 1 extra GB of RAM for 25 euros here in Spain.