You have a counter until you hit the next Hyper character above the recruit button. If you want to get specifically her, then recruit on the second banner by pressing the arrow on the right of the screen when you open the recruitment menu.
As for a combo, you can use Tio + Vionne, as thats quite a strong one. Another character that might be useful is Irina as she can target the Nun. If you pulled Nady instead of Maria, she is quite strong too, so you can also use her too.