I bought my game through "Steam", and my free 30 day game time is expired.

How do i add a 30/90 day game time card to my account? The only option i see at the Mog Station is "steam wallet". But if i choose that option...it does not tell me how much money i need to add to my steam wallet.

So..i would rather just buy a time card from amazon, but under my account there is no payment options other than Steam wallet?