Well..while it is good to learn a developing tool like Dreamweaver...unless you want to learn programming scripts and all..I personally go with having a developer put it together for you.
Have the layout drawn out on paper or something and tell the developer what you want and where..the developer will even have suggestions to help make it better.
But..like I said, it is a VERY good idea to have some idea of what it is you need before you embark on such an endeavor....don't forget that if you are selling things then issues like order forms, payment and so forth need to be ironed out. A developer will be able to help you out on this too.
However..keep in mind that not all of your customers will have Broadband, Cable or DSL internet. Many, like myself, will still have Dial-Up so when using graphics..keep that in mind..as graphics with too many kilobytes will just take to long to load.
Anyways..this is just my opinion..I do, however, wish you much success on your business. You will do great.