footer displays under sidebar?

Hello, Im using the Fishhook budypress theme, and I made an edit to the footer.php and header.php filkes. The header and the rest of the site is fine, but the footer is no longer showing up at the bottom of the page, but under the sidebar? Is there a way to undo this? are the core files ( footer.php, header.php) stored anywhere on the server that I could restore from a backup? Thanks!