I'm sorry but in my opinion the lorry thing lets you down.
It looks like a bit of clip art coupled with a distracting animated banner which you have just learned how to do.
Home button should be your logo and also appear at the top of your menu, not the bottom. It is one of the most used pieces of navigation on any site (apart from the back button in the browser) -don't make it hard to find.
Your images are not too bad but I would look to improve them wherever possible. You are selling something where the look of the thing is really important. Just look at asos.com and how complete gorgeous their images make this jewellery look
http://www.asos.com/cat.asp?SF=1054
In your shipping info you say you will ship within 7 days. In internet terms that is an eternity. Can you not offer to ship within one working day? or two? I would be looking for a site that can ship same day because that indicates they have the stock and they aren't going to be let down by problems higher up the supply chain.
Once you can offer same day dispatch you can offer next day delivery and this will lead to a lot more sales for you. Maybe you could offer it on just part of your stock, if not all. Choose the best sellers to try this with.
Also you are asking people to register to shop. This is madness. You don't have to register to walk into H Samuels. There is nothing annoys me more than some internet shop I am not going to buy from above twice a year forcing me to invent and remember a password "Just give me the d**m bracelet why don't you!?"
If I ever do come back I won't remember the password and this will be even more annoying.
So to improve your sales I'd say make sure your images are beyond reproach, make sure you can send the order out quickly and let people check out quickly without having to give out more personal information than is required to buy and deliver the goods. And for good measure get rid of the crazy lorry.