how to email all my forum members & how can i update?

hey guys as in the title how can i email all of my members with one email?
also i am on PunBB 1.2.17 how can i upgrade keeping my theme and topics ? www.linux-forums.co.uk
thanks (by the way the link isnt an ad its so that people can see the theme and tell me if i can keep it with the upgrade and how)
thanks again!