There are so amny childless couples who are waiting to adopt a baby. It is not an easy thing to do, but if you want to do it for the best interest of the baby that is a wonderful way to go. Someone in my family was a adopted, had a wonderful life, and later in life was able to find his birthmother, who always missed him, but she knew it was the right thing to do. What happened to her was simular as your situation. Already one child and financially not able to support a 2nd child.
Did you see the programs on tv, that you now even can find people that are willing to keep you up to date about the progress of the child or sometimes you can interview the new parents so you can feel comfortable with the family.
I hope you are strong enough to follow this route, if you do not want to go for an abortion.