First of all, Welcome to the club mate. Introduce yourself in the newbies section.
Well your that piece of plastic unfortunately goes real fragile after 15+ years and tends to break when careless people take out the stereo/install a new one.
Dwayne(dstocks) has brand new ones from japan for $185 .. which is incrediably cheap compared to Mitsubishi Australia $400+.
Send him a PM if you like, i would very much doubt you'll find one in good nik at a wrecker but you can try it lol.
Otherwise, the hole above your stereo you can just get a blanking plate or a pocket

... Autobarn sell the pockets.