Button Colours on the Cart (and possibly elsewhere)

G'day, I'l like to be able to change the colour of the button on the shopping cart page.
http://www.flaminmongrels.com/store/cart/
You'll need to add an item to the cart I guess to see the colour.
It is currently Green background with Grey Text - really hard to read.

Also

On the next page - the checkout page - http://www.flaminmongrels.com/store/checkout/ - the form field title for Postcode is "4213" Not even sure how that happens?

Thanks,
Brett