gogle adverts with the right keywords?

hello,

i run a osCommerce online shop for body jewelry:

https://www.jewleryworld.net

an already have my google adverts as a banner at the bottom of the page.
Now i get only a few clicks every day, and i know i would get more, if i can somehow show different adverts.

does someone know how this adverts work? is it from the keywords in the shop?

i only get adverts from companys in my business, but i would like to have adverts about high-profile google words, like:

game cheats,
christmas,
ebay,
harry potter.

i have enough visitors on my page, this is not the problem...

thanks,

patrick

1. wrong forum
2. wrong language

but anyway:

3. banner at the bottom of page is the most wrong place for ads
4. create content that fits to the desired ads!