No worries about the speedy reply, we all work, family etc, but we do take a moment and power answer users questions for a while before we vanish back into the real world
OK to use google now :
You need to be running the latest 2.8.17 (check the OP as over weekend there were some updates which added news GAPPS which include Google now etc. So its possible that you may be using the first update from friday. check this, download and update (flash straight over. (back up as always)
Then you should be able to hold the home (virtual button down) to access google now and you will also see a google icon in app drawer.
Regards