It may be the hair slowing you down though to be honest, your system sounds pretty decent (though you may want a beefier display card).  Did you set Poser to use more processes than just one? This may be slowing things down if you didn't. I myself am on a P4 with 2Gigs of Ram and a 512MB ATI card.  I have Photoshop, Poser7, Windows Media Player, Outlook Express, Firefox and IE running. My renders or a single character with hair usually takes a bit less than three or four minutes depending on the hair and textures. That's at the highest setting.  

You should fire off an email to tech support, as there may be something else slowing things down that you're not aware of.