Where can I purchase Ivona individual voices?

[BrockLanders]

I just upgraded to TextAloud 4 and added an Acapela bundle to my order. The Acapela voices are fantastic but I've decided I'd also like to have some additional Ivona voices as well (I have Emma from my previous TextAloud 3 purchase). The home page seems to indicate I can purchase Ivona voices individually but all links go to the TextAloud bundles with Ivona voices.

As you'd expect, I don't want to purchase TextAloud a second time just to get additional voices. Where can I purchase Ivona voices individually?