More than likely, IP forwarding is disabled (as is default). You can enable it by following the directions here: http://www.ducea.com/2006/08/01/how-to-enable-ip-forwarding-in-linux/
If IP forwarding is enabled, then check your firewalls on Windows, the OpenVPN server, and the host on the 192.168.0.0/24 network. Make sure the Pi is set to allow forwards from the two networks in its firewall.
Since this is a probable configuration issue, you will need to make sure the routes are announced.
server.conf, you will need the following:
push "route 192.168.0.0 255.255.255.0"
route 192.168.0.0 255.255.255.0
Then create the directory,
/etc/openvpn/server/ccd, and then create a file with the name of the common name of the certificate of the server. So if the server's certificate's common name is
foo, then create the file
/etc/openvpn/server/ccd/foo and put in the following:
iroute 192.168.0.0 255.255.255.0
Then restart both the server and all clients.