Unless it's rusted through, you can probably polish that thing up with a dremel.
You might be able to find replacement plexi online, but your best bet it to buy some and bend it yourself. I know it's a tricky task, but a heat gun isn't too expensive, and neither is plexi.
What sort of overlay do you have? You should probably...
1.) get a heat gun ($15)
2.) remove the control panel and take off all the plexi and remove the overlay (with the heat gun, if necessary)
3.) polish portions of the control panel that are still showing (like the triangular sides portions) with a dremel
4.) bend yourself a new piece of plexi, using the control panel as a guide. just get it hot with the heat gun and it'll start bending
5.) paint the showing portions of the control panel or add a new overlay
6.) attatch your plexi on top
If you're gonna bend your own plexi, do it BEFORE you make the control panel all nice and pretty again, but AFTER you've cleaned it. You don't really need plexi, either. Operators add it for durability, but if you're not going to abuse the machine then you really don't need it. It doesn't need to be idustrial strength. It just needs to be idiot-proof.
I only recommend fixing it over buying a new one because I think you're gonna have a hard time finding a new one that's better than the one you have.