Basically, you will be interviewing as a new graduate and you will have to matter-of-factly contend with the fact that your resume shows you have yet to practice in 3+ years since graduation. Don't get extensive; simply offer, "I elected to stay home with my new baby. She is older now and I am ready to enter the work force." Do you have a nursing school friend, former teacher, or other nurse that you know that you could role play a job interview
with? Make sure you aren't reeking of concerns about your own competence.
I would probably start by doing some intensive continuing ed hours. I know you were hoping to make money, not spend it, but it sounds like you need some confidence to "start thinking like a nurse" again. You might try to find some patient assessment classes or some cont ed in the area in which you hope to enter.
You could reapproach your school you graduated from and see if they would allow you to "audit" your leadership class, which would get you back on to a floor setting and function in a nursing role with some support.
You could apply to nursing agencies that provide "attendant care nursing" opportunities. Attendant care is providing 1:1 care to a patient in the home over a period of time (usually 8-12 hours). These are usually tech dependent clients (children on vents, bi-paps, etc.) what's needed here is the ability to do excellent care on one person at a time and do in in the home of and on the terms of the client family. It carries its' own unique challenges, but does not involve trying to manage masses of data on a dozen or more patients.
Then just stick with it and hang in there. remember that the care of your child has given you experiences and the care of your child was "colored" by your nursing education. You may have been doing more nursing than you think in the past three years. try to find a mentor; perhaps an old nursing school buddy that has been working the last three years and is willing to be your supportive person.