I run a gift shop site that gets slightly better than that but not a great deal better.
You need to concentrate your ads exactly. Don't be generic, use precise phrases for instance if you are selling wine, don't just advertise for wine. Name the grape or the vineyard if it's famous enough.
Your ads should look more like this;
Landermans Cabernet Sauvignon
Deliciously smooth, with a fruity after taste.
30% off during April.
Not like this
Lovely Red Wine
We have some at our site
Come visit this lovely site.
I'm not saying your ads like this but you get the idea.
The customer knows what to expect when they get to your site. Less bounces this way.
Expect a bounce of between 50% and 60% it takes time to build an ecommerce site remember you are competing against all the famous companies out there and especially Ebay and Amazon, your site needs to be smooth and quick, check how long it takes to load a page, if it's too long people get pissed off and give up. I know I do.