Our site may come up above yours on Google because we most likely have more inbound links and have been indexed by Google longer than you have.
In fact, our search engine pages are designed to return high results for you and enable people to click through to your site.
If you would like to increase your Google rankings, please read our FAQ How to Get Better Search Engine Results.
If your rankings have changed on Google, we can't specifically tell you why. Google changes things often. If your site was brand new and had no ranking before Google picked up our pages, their system may have been simply guessing your URL (website address).
Again, your best bet is to follow our suggestions about increasing search engine results.