H.W.
I agree with the other posters: find someone who can take your girl out and make her feel special. It's great that she wants to help. Or find an experienced baby nurse who can handle taking a four-hour shift with a colicky boy. (I did this as a nanny-- took the squawky baby while Mama spent time with the older one. I did a lot of walks with a newborn in the bjorn so mom and the older child could get a nap, too.)