My son has one breeding female and she will eat them as quickly as they come out. I don't what type of guppy you have but typically she wil now have no color (or light color) and be at least twice the size of the very colorful males. If she is really pregnant, which i an betting she is, she will have the babies in about a month.(I think that is how long. truthfully i have never looked at a calender. I'll let you know for sure because his girl had her last set on christmas and due very soon.) Also as a rule of thumb if you have a male and female together you can just about put money on it that she is pregnant.
If you want to save them pet stores carry breeding tanks that are same and very cheap. Just go in and ask someone about them and how they work. They should know that info if not pm me and I'll help you.