In $\triangle ABC$ let $D$, $E$, $F$ be points on the sides $BC$ ,$AC$, $AB$ such that $BD:DC=2:1$, $CE:AE=2:3$, $AF:FB=5:4$. $K$ is the orthocenter of the $\triangle DEF$. $G_1$, $G_2$, $G_3$ are the centroids of $\triangle EKF$, $\triangle FKD$, $\triangle DKE$ respectively. If the area of $\triangle ABC$ is $1080$, then the area of $\triangle G_1G_2G_3$ can be represented as $\frac{a}{b}$ where $a$, $b$ are coprime. Find $(a+b)$.