Probably best to start here to get an understanding of the software and the code:
It's very doable. And you'll have a better site.
After you work through the tuts Rik gave you, have a look at Not Just A Grid rapid prototyping system. This will help you create the framework for your page layout.
Replace the Flash slideshow with jQuery. Flash doesn't work in iPhone/iPad/iTouch devices but jQuery does.
Have a look at Project Seven's Menu Systems. Their products are rock solid, designed to work in DW and they have excellent support.
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