原签证已过期 does not matter at all as long as your H1B approval notice is valid which I am sure since you have been holding H1B status for just 6 months.
I guess what you want is a new H1B stamp with which you can go back to China without bothering getting the stamp there. However, you should have kept the I-94 card.
Right now, you are the same as being in China now because the I-94 is gone.
You have to wait or let your boss expedite the process for you. You boss can say something like how important you are and what the cost or loss would be if you were absent per day etc.
If your employer is a big company, let a top executive sign the letter. If your employer is a small company, let your senator or congressman sign the letter.
Then fax the letter to the consulate.
In one words, it impairs the interest of the employer if you can't get back on time.
I know people who had problem like this and succeeded by doing this way.
Good luck!