My first electronics project

The Outside, with a few parts taken off

So this might be a bit ambitious for a first electronics project but I hope to conquer it. I want to use an arduino uno to control this toy front end loader. I've had this toy since I was little, like crawling on the floor little. Now I'm 23 and its been collecting dust for the most part. I recently plunged into the world of arduino and thought it would be a good project to learn some electronics and put the microcontroller to use.

The inside

So I took it apart and found out it makes smoke!!! I never knew this as a kid,  I guess my parents were paranoid of fire or something. anyway, that isn't all that crucial to me as a feature so if I need space I'll scrap that part. other wise it looks pretty simple. Well, it should be simple at least.  Perhaps my famous last words.....

Terminal for Motor connections - it connects the controller's wires to the motors'

Now these electronics are probably like 20 years old. I'd like to control them with the arduino, eventually perhaps by using a zigbee card but for now just straight programming a sequence into the microcontroller would be a good start. The wheels seem to be powered by two motors, and the scoop also seems to be powered by two motors, each motor controls a function. 1 motor for the left wheels, 1 motor for the right wheels, 1 motor for the scoop's angle, and 1 motor for the scoops elevation.

Inside of the controller

This is where it gets tricky for me. Being an IT student, I really have almost no knowledge of the electronics hardware world. I can light up an led and make it blink, but that is simple. I have no idea what type of power requirements the motor's need. The controller holds 4 1.5V D batteries

Side of the Wheel Motors, one turns the left wheels and the other turns the right wheels.

So the first step is to quantify what type of power it takes to run the motors, then I will be able to figure out if I need a secondary power supply in addition to the arduino. If you have any tips or suggestions on how to go about doing that feel free to comment.