I definately agree with lisa, if your not getting much traffic, then now is the time to do it. When you get your new domain name you could just forward all traffic from your old domain name to your new one. And to all those curious, a 301 is a "permanent" redirect. So say you have your site on
http://www.mysite.com but you decide you dont like the name or want to change it or whatever the reason. You can set up .htaccess or in some cases do it automatically depending on your host to permanently redirect all incoming visitors from your old domain name to your new one.