I bought one of these of fleebay The price at the link below is high but the link gives a good idea of what I have used in my camper.
http://www.acehardware.com/product/index.jsp?productId=2122840
Later I installed an electric wall heater link the one below.
http://cgi.ebay.com/Fahrenheat-Electric-Wall-Heater-2000-W-240V-FFH1615_W0QQitemZ330377107848QQcmdZViewItemQQptZLH_DefaultDomain_0?hash=item4cec029988