In my 2001, the DVD player is located near the spare tire. If you lift the carpet and look to the right, behind the tire jack you will see the DVD player. You will probably need to remove the jack to eject the disk. With the key "on" there is a slide button cover that says "open". I think there is an eject button under the cover which is pressed, but sliding the cover may be all that is required to eject the disk.
There are two 2003 DVD upgrade disks for sale on E-bay.