You're right. I was scratching my head over that one as well. That's what I get for posting before I have my coffee. :O)
You'll find that Augustine's veiw changed over time which he freely admits in his writings; especially with the Pelagius heresy. Here is an excerpt from his works, "On Grace and Free Will".
Chapter 41 [XX.]-The Wills of Men are So Much in the Power of God, that He Can Turn Them Whithersoever It Pleases Him.
I think I have now discussed the point fully enough in opposition to those who vehemently oppose the grace of God, by which, however, the human will is not taken away, but changed from bad to good, and assisted when it is good. I think, too, that I have so discussed the subject, that it is not so much I myself as the inspired Scripture which has spoken to you, in the clearest testimonies of truth; and if this divine record be looked into carefully, it shows us that not only men's good wills, which God Himself converts from bad ones, and, when converted by Him, directs to good actions and to eternal life, but also those which follow the world are so entirely at the disposal of God, that He turns them whithersoever He wills, and whensoever He wills,-to bestow kindness on some, and to heap punishment on others, as He Himself judges right by a counsel most secret to Himself, indeed, but beyond all doubt most righteous. For we find that some sins are even the punishment of other sins, as are those "vessels of wrath" which the apostle describes as "fitted to destruction;"241 as is also that hardening of Pharaoh, the purpose of which is said to be to set forth in him the power of God;242 as, again, is the flight of the Israelites from the face of the enemy before the city of Ai, for fear arose in their heart so that they fled, and this was done that their sin might be punished in the way it was right that it should be; by reason of which the Lord said to Joshua the son of Nun, "The children of Israel shall not be able to stand before the face of their enemies."243 What is the meaning of, "They shall not be able to stand"? Now, whydid they not stand by free will, but, with a will perplexed by fear, took to flight, were it not that God has the lordship even over men's wills, and when He is angry turns to fear whomsoever He pleases? Was it not of their own will that the enemies of the children of Israel fought against the people of God, as led by Joshua, the son of Nun? And yet the Scripture says, "It was of the Lord to harden their hearts, that they should come against Israel in battle, that they might be exterminated,"
As Augustine states, God turns the will as He so pleases and changes the will from bad to good. He has Lordship over our wills.
I understand the mistake :)
BTW, Augustine can be quoted as seeming to appear to deny free will; but he doesn't.
I can find dozens of such examples from his works. Here he is in City of God (which I reread recently) Book 5, chap. 9 Now if there is for God a fixed order of all causes, it does not follow that nothing depends on our free choice. Our wills themselves are in the order of causes, which is, for God, fixed, and is contained in his foreknowledge, since human acts of will are the causes of human activities. therefore he who had prescience of the causes of all events certainly could not be ignorant of our decisions, which he foreknows as the causes of our actions.
*The more you read Augustine the better you will understand he does not deny free will or the necessity of our cooperating with Grace.
Book 12, Chapter 9 "I likewise know that when an evil choice happens in any being, then what happens is dependent upon the will of that being; the failure is voluntary, not necessary, and the punishment that follows is just."
*Dozens of such examples abound.