Hey Guys thanks for all the assistance.
Despite most your comments and i really do appreciate everyones input i thought id have a crack at what my dad suggested first off. (gotta listen to the parents hehe)

Anyway a bit of an update here...
* Purchased a A/C Fan Motor for $10 from the wreckers (bargain!!)
* Purchased a new 12v Motorcycle Battery (smallest size i could find) for $69
* Compared the old motor to the new motor simply by listening how they both sound when connecting to the battery. I was very impressed with the A/C motor as it looked like it was much much much faster than the original motor, all i need to do now is mount it permanently and give it a test run.

Now to answer a question from a PM, the motor that i was referring to is the motor that is normally housed on the passenger side of any car i believe it is used to operate the blower to blow the air out of the air vents in your car. after pulling one out today it reads 300watt down the side.

I will report back how im going as there may be some of you interested in how this actually performs in the water. I cant wait to give it a go in the water!