Getting the news can be very overwhelming and stressful. It's normal to be in shock and go through waves of different emotions at times.
While I don't have personal experience with this, I did want to pass along that there are a number of organiazations out there with information and support resources for families dealing with congenital heart issues. Little Hearts, CHD Families, Children's Heart Association, Children's Heart Foundation. If you search Congenital Heart Defects (CHDs) the CDC has alot of info and resources listed. The American Academy of Pediatrics also listed physicians and specialists– might be a place to start for a cardiologist. I mention these because perhaps these organizations have educational resources or could support you in finding doctors, local services, etc.
There's a great article from Cincinnati's Children's hospital titled "My Child Was Diagnosed with a Heart Defect – Now What?". I can't post the link here but it'll come up if you google. It's from a pediatric cardiologist and lists out step by step things to do after diagnosis along with links to resources. She also provides a list of questions to ask the doctor/surgeon which may be helpful to check out with the appt coming up.
Best to you and your family...