When functionality is as important as design

I think I am quite good in making websites, at least as good as possible for somebody who has a limited knowledge of IT.
I like to play with colors and images, to write my text and make a nice looking site.
But when it comes to really complicated things like building a good functioning ecommerce website I am finished.
For something like that you really need a good ecommerce software, something easy to use and customize, where you can play with colors and images, where you can write your own copy and let the software do the difficult and boring part, which is to make it WORKING.
And many software’s, the good ones even offer you the right ecommerce web design, something you can see done, and you can chose, may be adding something to make it unique.
An ecommerce website must be nice looking, but mostly must be functional and who better than an expert can make it so?