HMMT 2006 G5

Triangle $A B C$ has side lengths $A B=2 \sqrt{5}, B C=1$, and $C A=5$. Point $D$ is on side $A C$ such that $C D=1$, and $F$ is a point such that $B F=2$ and $C F=3$. Let $E$ be the intersection of lines $A B$ and $D F$. Find the area of $C D E B$.