Looking at the crystal in one of your pictures, it shows this tx/rx combo works on 27MHz. Also the name of the plane says enough. This is one of the rtf packages that is very limited with regard to connecting things to it. Still, you can have a lot of fun with those packages. I think you are on your own, unless you can find a schematic of the tx.
Are you located in the US? If so, find a cheap 4 or 6 channel GWS transmitter and receiver on 72 MHz (For most of Europe, you will need 35MHz). These sets do have trainer ports and give you some nice possibilities.
Good luck!