Need Some Wiring Help on a Go Kart..

[rawfuls]

Bought an UBER cheap Go Cart/Kart whatever the hell, from an Auto store a LONGGG time ago.
Finally dusted it off, and had some uber fun in the backyard salon with it.
Still needs the steering fixed, and had a negative wire pull off the on/off
After being the idiot I am, turned a 1 minute job into a couple days worth of work.. Well, waiting really.
I kept the iron on the terminal too long, and melted the terminal off since it was heating the plastic up too!

Anyways, the switch is a SPST (I think, On/Off switch, with two prongs on the back). Looks just like this baby:


As you can see, there's only [B]2/B] terminals on the bottom/back of the switch, only has On/Off.

Since I don't know the amount of AMPs going through this (Though the battery is on the back, too lazy to pull off the covers and such), I want something heavy-duty like this:
http://www.radioshack.com/product/in...odsInSession=1

Note 3 pronged

or

http://www.radioshack.com/product/in...odsInSession=1

Where I have no idea how many prongs..

Anyways, in short, since I'm electrically retarded, how do I wire this?
I'm a bit scared to try shorting the two wires from the switch and seeing if the circuit closes (by connecting the two wires) and turns the baby on, or if those two wires are actually the battery leads (which makes no sense to me, but wanna make sure)...

In short... How do I make sure I'm wiring the new 2 or 3 pronged switch correctly without blowing the house up..

Thanks!