please help! H-1B travel

Hi,

I am a H1B visa holder but without the stamp on my passport. I have been the US for 4 years. transfered from F1 to H1B 2 years ago. Now, I want to travel to Australia for 2 weeks to visit my wife. I called the US embassy in Australia, they told me that I'd better go back to China and apply for the H1B visa there. then I called USCIS, they told me the same thing. they said because I don't have the stamp on my passport so it is possible for the US embassy in Australia to reject me.

the problem is I only got 2 weeks vacation and the flight tickets are so expensive during New Year time. What should I do?

1. Can I go to Canada to get my H1B stamp before I leave for Australia?
2. What's the difference between Canada and Australia? is it hard to get H1B stamp in Canada as well?
3. If I am rejected in Australia and go back to Beijing. How long will it take to get my H1B visa?

Thanks for your help. any information will be appreciated!