to clarify my point:
With this special setup of two OS's running simutaneously on the same machine, I don't know if the normal MySQL port 3306 is accessible for Linux or if it can be accessed “from outside”. But since you can connect til your Apache server running on Linux port 80 is accessible!!!
Therefore HTTP-tunnelling should work, if direct connection is not possible!
But of course I don't know this special configuration. Do the 2 OS's share an ip or not for instance …