Driving a Nikko RC motor and a servo

Hello everyone.

This is my first post to this forum.

I've been working on a PC controlled RC car project for a few weeks. I got an old Nikko RC car and i've disassembled it completely :D. I am using an Arduino board with a bluetooth module and a L293D motor driver shield both ordered from eBay.

So far i removed the stock reciever/motor driver board and the stock servo. The stock servo had 6 pins for connection to the board. I replaced it with a standart RC servo i bought from my local electronics shop and it fitted (luckily) the car perfectly :D. I could use the servo for the steering with the knob servo template came with the IDE. I managed to drive the motor with L293D but the IC seemed to overheat. I measured at full power the motor draws about 0.4 A from the battery. Is that normal or should i replace the IC with L293B?

The thing is, i want to use the serial connection with bluetooth to operate the car. I've managed to link the bluetooth module with board and pair it with computer. I did a few examples (led on/off etc.) with serial and so far it seemed ok. But i am absolutely begginer to coding and i want to send the servo.write(val) functions val from serial. And also i want to use PWM with DC motor to control the speed. Could you help me please?

I know it's a long text, sorry for that :D

Are there any markings on the motor, like "540"? All the electric R/C cars I've had have drawn way more than 400mA (peak currents can be tens of amps), and I've always used either mechanical speed controllers with a servo, or FET electronic speed controllers, both of which can be driven by the Servo library.

Actually, i didn't disassemle the differential and the motor. So i have no idea what's written on the motor. The stock car had MOSFETs on the receiver/driver board, so i guess it doesn't need a mechanical speed control. I will attach pictures later.