Hmm, the not having the Specware software might come down to being the biggest problem if you wanted to keep using the current communications (COM) board that your station has. The Specware software is how you'd be getting into the brains of the COM board between the modem and datalogger. From that, that's where you can change the information as to where the data is sent in my case the difference between the Spectrum website and our servers. Currently we are using both their older version and newer version of the GPRS equivalent here in Quebec but we also use another proprietary board that can collect and transmit the data as well as using a RaspberryPi to collect it as well. So there are outside options for getting the data without using the parts Spectrum has to offer and without having to get a copy of Specware but it would probably still be worth it perhaps.
As far as the data format, first it would depend on what you have connected to which ports of the station outside of the temperature and humidity data if I'm remembering correctly. I'll see if I can find some raw data and I'll post it because the data isn't encoded in anyway between the datalogger and COM board and in the setup I use it's not encoded even in the transmission.