You need to replace the leaf and it needs to be the correct size. Myself or one of the guys will be able to help you out there. As a temporary fix though... get a few strands of wires and push through the hole where the contact button was. Then twist together on the end of the leaf switch and solder the tip so wire and leaf switch are one.
This will make the leaf switch operational again so you can continue working on the game and sort out anymore faults while waiting for a proper replacement to arrive in the post