The ckt you are using is only for momentary remote control. e.g. an output will be only activated till you keep pressing the Tx button. or in other words you have to Transmit a signal constantly, which is not good for battery or portable operations.
I think you need some kind of toggle ckt. which will toggle it’s output on every input. and holds it’s state. thus your relay will be ON/OFF by only pressing the button for once.