It's worth having a look at something like ExpressionEngine (about $300) or MODx (free), as they are better suited to someone with no backend experience. Others, like Drupal and Joomla, are somewhat more complicated, but they are also free. Drupal is a massive workhorse, but it takes a fair bit of work to get your head around it (I gather, as I gave up early on!)
Don't know much about cms though, any specific ones i should look at?
I don't mind doing it this way as long as its not too complicated.