You can get the ketchup from amazon.
http://www.amazon.com/Whataburger-Condiments-Pack-Spicy-Ketchup/dp/B00CUFUZNA/ref=pd_bxgy_gro_text_y
Kind of pricey though...
Mustard Nazis hot dogging it!
I miss What-a-burger. So good... and this is weird but I like their salads.