Looking for high-speed wireless transceiver module.

Hi, I'm looking for a module that can do 4 Mbps over 100 - 250 m. I've found a few 2.5 Ghz modules but they can only provide about 1 Mbps. A simple digital interface is preferable. This will be put into a model submarine for transmitting the acustic array data to a PC. Infact, it doesnt have to be a transceiver, but just a transmitter, then I would add another slow module for control signals. Any suggestions?

Regards,
Mark