Congrats to your sister and husband! It's such a blessing when a family adopts a child, no matter what the child's age.
A good friend of mine was unfortunate in that she waited too long to start a family. She was unable to conceive after a lot of painful tries. Fortunately, after emailing her the links I posted for you and doing some reading, she was able to adopt a beautiful toddler.
Good luck to you! Feel free to email me if you have any questions. I will do my best to help! =)