Here are drivers for the CH340 / CH341 USB chipsets that can be found on a lot of Arduino clones.
I found the OS X Driver here:
And the Windows Driver here:
I have personally used the OS X Driver : OS X 10.11.4
I have personally used the Windows Driver : Windows 7 Home Premium 32-Bit.
I believe the original source, of both of the files, is WinChipHead.
Disclaimer: I am not responsible, at all, for the files, or you using the files, or things working or breaking because of the files. Use at your own peril.