Select the green vertices along the whole bottom of the dash and extrude them inwards to give it a nice lip.
Now let's put the windshield on the car. Create a box and position it at the position shown in the picture. Adjust vertices to get a shape similar to the shape shown in the picture.
The logical thing would be to do a series of extrusions to create the frame of the windshield but that's rather tedious and time-consuming. There is an easier way to do this. Start by creating a spline by going to: Create->Shapes->Line from the main menu and drawing the line shown in the picture in green. Just draw half the line because we are going to add a symmetry modifier. Make sure the vertex on the line shown by the red dot has an x-coordinate of zero.
Now comes the fun part. Select the polys shown in red on the box you created and then click the "Extrude Along Spline" button then click the spline you drew. This does all the extrusions for you automatically. Add a symmetry modifier and adjust any vertices that need adjusting. You will also need to delete the polys at the center of the car.