RE: need information on old futaba FP-T7FG/k fm 7chan radio
I would just call Tower Hobbies or Hobby Services and they will know what type of battery to use. It is most likely a 9.6v 8cell NiCad or NiMh pack and just needs the correct connector for the inside of Tx and the correct polarity.
Perhaps you could reply to one of the threads from the links I posted in this thread.
I think I used to own a radio just like this.
The Wall Chargers they usually provide with the radios are fairly inexpensive, although I prefer something like the Triton II.