I need a light cover that is 11 inches all the way across and approx 3 inches deep with a screw in lip of 8 and 3/8 inches wide also white, can you get me one or two?

If this is a globe or lens on a light fixture, just giving us the dimensions is not enough.

You need to determine the manufacturers name that made the fixture, determine the catalog number of the fixture, to locate a replacement globe.

If you have a sample globe, you can bring it to a local lighting supplier and ask them to help locate a replacement.