Hmmm the problem is as already stated really, 1) your site does not portray any trust or realism and I would click off before even seeing any products, if I did see products I wouldn't buy from the site and 2) you have completely the wrong products. Firstly they are all low value low margin, how many cans of WD40 will you need to sell to make a living? Which brings the second point, no one goes online to buy WD40, De-Icer or the other items you're selling.
People may buy them online at Halfords or big motor factors along with various other things on the same order, but no one will buy WD40 from you, as you've proved over the past year.
I don't want to be negative but you're going about it all wrong, as was I when I first started in the e-commerce game. You need to go out and find a niche, find some products that you can properly market, make profit on and also be competitive with. You'll need a new website as well really, either go down the Opencart and theme route as suggested or look at something like Magento Go, at least their themes seem more "real" and trustworthy to a customers perspective.
Stop the AdWords for now, you must have a very high bounce rate, I'm not sure where you get 2% from, as you say that you're paying for traffic but getting no sales would indicate to me (both from what you say, and my experience of your site) a very high bounce rate. You can pay for people to go to the site until you have to re-mortgage the house and have nothing left, but ultimately however many people that gets you on the site, they aren't going to buy from you so you won't get a return on your investment at present.
On the plus side! The name "care 4 cars" has potential I think, it has keywords, it is what it says... how about you try and find out the best car care products like detailers would use, detailing tools, foam lances, buckets with stone guards and other foam accessories, clay bars etc.
Then fill the site with information, how to's, guides, links and other useful content then concentrate on that product range. As also mentioned you then have a clear audience - car enthusiasts.... there are many ways to market, but at least then you would have a clear and concise and fairly niche market to start targeting (if you get the products right).
Ignore the "me to" stuff, WD40? forget it. Find that niche, go where the customers are, invest in a trustworthy site. When you get enough traffic and enough conversions you can start to add in some of the cheaper, but related, upsell items.
