Hi Ying,
I am happy to hear that. That is a good news, you already a student in the US. That means you already have F1 visa. I'm happy with you.
I have talk with a person who works for a lawyer, and she said I have only a green card and I am not a citizen yet. I won't be able to do that. If I do that It may cause myself in trouble. Even I write a letter for you, It wont be work. It is because I don't have a job, I am a student. They will think I won't be able to support you. Moreover, I can live in the US because of marry with David. If I don't have David I have to go back home too.
You can use your family support this. If you have enough a good bank statement and your family money's statement that will help you better.
What about your Au pair program? Do you still working on it? Au pair program will be a better way for you to come here. You need to stink with an Aupair program and try your best to get pass the interview. This program will help you get your visa.
If you already a student in the UA, you will be ok. Don't worry you will pass the visa. If you have enough money support for the bank statement.
Anyway, We are going to have a baby next year. We are busy preparing for our baby and organize a room downstair. I also crazy with my two classes that I have exams every weeks. They are very different. So, I have many things going on right now. I just would like to let you know.
Good luck for your visa,
Chinda