Volume of the solid bounded by $x+y=1$ and $z=4-x^2-4y^2$ and $z=0$ and the coordinated planes

Question

$x+y=1$ and $z=4-x^2-4y^2$ how do I set the limits of integration for the integral $$\iint_D 4-x^2-4y^2 dA$$

As I know I have and ellipsoid and a plane not sure of how to get $y$ or $x$ especially in the ellipsoid form because I will just have one side (positive or negative) of the plane xy.

The integration zone is the one that contains the origin