If the first picture of the radio is the one you have. It looks like you can swap the black plastic façade out with a slightly larger home made one possibly backed by a sheetmetal plate.

You can get that textured plastic from Tap Plastics and cut it to fit. I used a similar technique to mount my Vintage Air control panel in my dash.

These days though, I'm not sure why anyone would not use their smart phone with Bluetooth, Pandora, an amp and hidden speakers for a completely invisible vastly superior sounding system.

Or do what I do and throw a portable Bluetooth speaker in your car an use your smart phone to drive it. I can use the same speaker in the garage, the house or wherever. They are getting really good these days.