I am also related to that family tree but the web page stopes at my ggrandfather below is a ancestors list. I have only done a little reserach on my family tree but have been very luck finding good information on both the CUELLARs and GRAVES line.

Antonio LIZARRARAS
Bartolome de LIZARRARAS Y CUELLAR
Asencio de LIZARRARAS Y CUELLAR
Bartolome de LIZARRARAS Y CUELLAR
Jose Miguel CUELLAR
Jose Domingo de CUELLAR
Matias
Felipe CUELLAR
Hesiquio CUELLAR
Elia CUELLAR GRAVES
Me