我现在是H1身份在美国，前不久收到去加拿大登陆的通知，正在办去加拿大的签证。因为不是主申请人，所以我不一定要留在加拿大，登陆后就想马上会美国继续工作。
我担心的是我入境美国的签证早已过期好几个月了，如果我去了加拿大，哪怕只有几天，不知道能不能顺利回到美国呢？期间具体程序又是怎样？希望有经验地前辈可以指点指点。
曾经听说30天内往返就没问题，但是昨天网上搜到美国边境的新政策(连接如下)，着实开始担心：New Requirements for Travelers :
The Intelligence Reform and Terrorism Prevention Act of 2004 in the US holds that by January 1, 2008, travelers to and from the Caribbean, Bermuda, Panama, Mexico and Canada need to have passport or other valid document to enter/re-enter the United States.
The new policy will be implemented by phases. While by January 8, 2007 all kinds of air and sea travel to or from Canada, Mexico, Central and South America, the Caribbean, and Bermuda, will be brought under jurisdiction, by December 31, 2007, the rule will cover all land border crossings as well as air and sea travel.
http://www.mapsofworld.com/usa/visa/canada-to-usa-visa.html
不知道以上是不是真的，难道我一定要回中国拿美国的签证吗？或者登陆后我就能马上去美国驻加拿大领事馆办理入美签证呢？心里很没底……