Ok, I probably wasn't clear. I need (or want) the weather station to connect directly to my existing wifi network access point.
@OP: You're probably stuck because the RN-XV is in the XBee form factor. That does not mean it's a ZigBee network module. You get WiFi (as the RN-XV), GPS, Bluetooth, ZigBee and probably other modules in this form factor, it's not limited to one usage. It does connect to a WiFi network but it's configured and used through the serial interface. I use mine to gather moisture soil and temperature data which it sends directly to my server, over the network not by using another PC.
When you say serial interface over WiFi, I'm not sure what you mean. So like a Serial.println("hello"); would transmit "hello" over WiFi, but to where? Using TCP/IP?