some dumb questions about servos and receivers

I am currently building an brushless revo. I have installed one traxxas 2055 high torque servo for steering but it struggles to turn the wheels at a standstill. Is one servo enough?

By the way, I am using the radio and receiver from my old super hornet. Could this possibly be under-rated for a high torque servo. Its hard to find the current ratings of this type of thing.

If I have to replace my radio gear, can anyone recommend a good 2 channel radio and receiver.

Thanks