Sorry your child's been diagnosed. It's a very scary feeling. My daughter was born this summer with the exact same defects as your daughter: a small ASD (aka PFO) and a perimembranous VSD, except my daughter's defect was large.
The docotr was right, these defects do not get larger, and the small ones have excellent chance of closing on their own, and normally don't cause any problems. Again, my daughter's defect was large, she was in heart failure at a very young age, and was booked for open heart surgery - well guess what? Her surgery was cancelled because her VSD started closing on it's own. My daughter is now 8 months old, completely off all heart medications and her defect is so small they expect it to close on it's own.
Try not to worry and just enjoy your baby!
If you search this forum you will find that questions and concerns about VSDs (holes between the lower heart chambers) are extremely common. A hole measuring 2.3 mm is small. These VSDs do not enlarge after birth; they can stay the same or get smaller, or even close completely. VSDs located in the perimembranous region (under the aortic valve) have a good chance of closing over time. Your cardiologist/doctor will observe your child for any signs of heart chamber enlargement, or abnormal developments associated with natural attempts to close the hole, such as the development of a membrane in the outflow tract of the left side of the heart, or prolapse of the aortic valve that can lead to valve leakage. These complications are relatively uncommon, and the prognosis for your child is excellent.