It's there Sandy...storefront>view>default_html5>template>footer.tpl
Scroll down to line 55 and read that line.
Then remove lines 33 through 47 after you make a donation (not required, but highly recommended)
That will get rid of the current copyright configuration.
You won't see the words AbanteCart because it's a php call that calls the block that contains the words you're looking for.
You'll need to learn a little about php or your going to blow up your website again.