I must agree with C4arl. The filter kept in a regular tank will have some ability to take care of the female during the wait and can quickly grow to accommodate the fry. I find a 10 gallon, 37 litres, tank is about right to keep the female comfortable and have room in it for the growing fry. Another option, between drops that you decide to save, is to put a bit of ammonia into the empty tank daily just to keep the filter bacteria alive and thriving.