phpnuke is a content management system like the ones i linked too in my above post.
did you check out that link? i really believe that if you find a good cms its your best bet. phpnuke is skinnable (meening you add your design), but every site ive seen made with phpnuke looks like any other phpnuke site. id'e suggest looking at the mysource cms, posted in my link above.
as for dreamweaver. it can write code for you, but it is usually fairly inificient and poorly coded.
as for design vs programming. personnally, i design my own stuff. but yeah, im more a coder than a designer. though i would say, that desgning for the web requires more technical background than desktop publishing. to design well for the web you need to know html and css. and no, html is NOT programming.
by the sounds of your needs, honestly, check out some of the content management systems posted in my above link. these things take care of all the backend stuff. you take care of the design and content.
other than that. php is a fairly easy language to learn, and once you know it, the posabilities are endless. if you REALLY want to do this yourself, you will need to learn php. there are no shortcuts.