If you have the RFID readers connected to a network, you could do this pretty easily.
You need to separate your project into two parts - getting the rfid info into a processor/microprocessor of some sort, and then moving the data to another location. Both are pretty easily solved with off-the-shelf parts.
The problem I think is that you're asking/googlinh about transmitting "RFID Information" in particular. Once you scan a tag, you basically get data. Data is pretty generic. People spend a lot of time working on moving data around. Once the tag information is in the computer, it's just a string you need to send over some sort of medium, and if your medium supports data, it probably supports any actual data contents, RFID or not.
I'm not too sure how many of these things you want to make; an easy if not cheap solution would be to just slap an RFID reader on an Arduino, together with a GSM module (for cellular communication), or a WiFi module. However, this is a bring-your-own-code solution. If you're hoping for something off-the-shelf, short of using an full-on desktop/laptop computer for each node, I think you're out of luck.
If you already have a lot of RFID readers, there are plenty of serial/analog/whatever bus to wireless adapters out there, but they're not going to be labeled RFID-specific. Again, think data, not RFID.