do I just enter 1579? (if so that's depressing! My example in the image below.)
This is correct.
dustcoin.com gives you the same estimates (and you get some of the altcoin profitability calculations there).
But remember, these $10 you mine today may be worth $40 in a year or so, when the USD against the Bitcoin crashes another 75 percent
(i.e. 1 BTC = 400 USD)