OK. It sounds like you in a bit over your head. I'm working on a semi-similar project, but I'm using an easier route to do it.
I need web based access to both data and control from several devices simultaneously. I don't want a full computer involved though.
My solution is an Arduino board with a Ethernet shield on it, that plugs directly into my router. The router provides the wifi, web access etc. The Arduino is the web interface and pulling data from the other devices. (It is also running some RGB lights nearby)
The base Arduino is also equipped with a NRF24L01+ based module, as are the sub units. This provides a simple, easy to use channel back to the base unit. The NRF24L01+ is easy to interface with and use, and has a reasonable range. If I wanted more, I might also add a 433Mhz unit with a proper antenna, which would work up to maybe 500m+
I'm not sure exactly how much complexity you need, but this might work out an easier solution for you.