Change Main Navigation Borders to Images

Hello,

On this site: http://alchemistrecovery.com

I'm trying to replace the main menu navigation borders with these images:

http://alchemistrecovery.com/wp-content/uploads/2016/04/top.png

http://alchemistrecovery.com/wp-content/uploads/2016/04/bottom.png

I belive these are the items:

.genesis-nav-menu border-bottom

.genesis-nav-menu border-top

Thanks in advance,

Casper