This may sound a little harsh but in Google terms, what you are trying to do isn't going to fly, at all.
Thousands of shopping carts appear on the web every week at present, seems to be a recession reaction but without people appreciating the complexity of the web, or the level of competition.
If you want to go ahead (I don't think this is a great use of your time) a few basic points to get in order:
You need to pick one site and 301 redirect the duplicate site to this. Having more than one identical/very similar website aimed at the same audience is technically against Google guidelines and in any event, will weaken both.
On the subject of 301 redirects, have a read through click here which will help you at least configure the site to be sure of correct indexing in one sense.
Your core need is to fill your site with unique and valuable content. This curently consists of manufacturers product data that is available in many other places. This will not interest search engines, or decent sites that might offer yours a relevant inbound link, which does help in search.
Neither should you use other people's content for core pages e.g. click here
Establishing a successful website depends on what you are trying to achieve. Just read an article on a local council website you might find useful click here Bearing in mind you would fall into their last category.
Much to learn and quite a time before you see anything come to fruition. The suggestion above to read through all the Google webmaster documentation makes sense, you might particularly like click here along with click here
Good luck if you carry on, just be aware that at least in search engine terms, you will not be seeing income through the site for a long time and the learning curve will be steep. Still worth going through if you are that way inclined.
Much as before will apply and you really do need to set the site up to function in one form. Found 8 different URLs for you home page (there may be more)and 4 other URLs for a page entitled Home, which is otherwise blank.
Much the same for product repeat/overlap, even in already indexed pages such as the example click here
Google do try to filter duplication but are not always successful and in any event, much better if you control how your site is indexed and therefore which pages can be returned. You might find this a little help: