There are quite a few concepts to wrap your head around when trying to create the sort of web site you are talking about, and have to agree with Ricardo that programming is for programmers.
That doesn't mean you can't become a programmer, but try to break it into easily digestible chunks, and start with learning in areas where there is a lot of community support, and plenty of open source material to learn from.
That being said, it takes at least a few years full time experience to get anywhere near good enough to design and architect a medium scale system.
I would even suggest looking at PHP (no platform war please - I'm actually from the other side), mainly because there are so many open source projects out there, and so many active forums. You may be able to find significant chunks of your app already written for you. Once you have half a dozen languages under your belt, picking up new ones becomes a lot easier.
Have you considered using off the shelf web app frameworks? Drupal, Joomla, Mambo, ..., etc.
That way you can get your feet wet without biting off more than you can chew.
Also agree with Cruachan, that at the very least, you need to get someone who knows what they are doing to make sure you are not shooting yourself in the foot without knowing it. Just because something works, doesn't mean its good.
Don't want to discourage you from learning to program, far from it, but please keep in mind that it is harder than it looks, and you must learn to crawl before you can walk, and if you try to skip the basics, it will bite you later. If this is a commercial venture, it will bite you hard.