Where i can find my stock rom
For finding other ROMs, Google is your best friend. If you can't find anything with Google, chances are that there aren't any custom ROMs for the phone. Any ROM that is compatible with the device will specifically list the phone. If it is not listed, it is not safe to flash the ROM and may result in hard-bricking the phone forever.

As far as the stock ROM goes, Google is again your best friend. Many manufactures post the stock ROM on their website for just this reason, however, if it is not there, you can always take a nandroid backup of the phone which also captures the stock ROM, allowing you to flash back the stock ROM if you wish to do so.