Answer

1, How long is it since your parents making the appointment till today?
My parents made appointment about two weeks ago.
2, Which US consulate?
In Beijing.
3, Any website to make the appointment?
No, I think you have to call them.

Don't worry, my hu*****and and I came to the U.S. almost 7y, we also never go back China. VO only concert if your parents want to immigrate to U.S.