You'll either need to stand up a SharePoint instance on one of your own servers or use a 3rd party to host your site. I currently use a 3rd party hosting company
http://www.frontpages-web-hosting.net/. I have easily created an externally facing SharePoint site using this technology for an Infertility Doctors and Clinics site located at
http://www.FindInfertilityDocs.com . Contact me from that webpage if you have any additional questions.