A lot of it depends on the answer to two questions:
1) WHERE is the ASD? (Near the top of the Atrium, or lower down?)
2) HOW BIG is the ASD?
If all the conditions are right, they may be able to fix it through a Catherization. A small (less then 1 inch) incision is made in the groin area, and the Catherization tube is inserted into a vein and slowly pushed up until it reaches the heart.
Several different instruments can be carried in the Cath tube. One contains a camera, to actually look around inside the heart. The other will inject a dye into the heart. The dye is slightly radioactive, so that it shows up on x-rays very well. They inject the dye and then snap several x-rays, so they can study the blood's flow through the heart.
The Cath tube can also carry a tool that looks like a closed umbrella. The tube is manuvered so that it is very close to the ASD. The umbrella is then worked through the tube, and through the ASD. When a button is pushed, the umbrella "pops open", and the doctor pulls back on the wire. The open umbrella then covers the ASD, closing it.
Another button disconnects the wire from the umbrella "handle", the Cath tube is pulled out, and the ASD is fixed! No scars
The problem is, no matter how they choose to enter the body, she very well might need surgery again later. Her heart will probably outgrow the repair.