Any RV store should have the universal ones. Use a dap of sealant on the screws and you're ready to go. We bought one at CW recently but took it back when I found that all that was wrong with mine is it wasn't installed correctly the first time - someone used non-plated sheetrock screws which rusted and broke in half. Four stainless screws from HD took care of things.
Interesting that yours is falling apart. My MH is a 2005 and I don't know if the cover was original or not, but it looked like it. It was still in good shape so I used it instead of the new one.
Bill
