Be sure to check out your patent attorney leads on the Internet, but take what they say with a grain of salt. It's easy to claim extensive knowledge and experience in patent trademark law, but you'll never know the truth until you do some detective work. Check out some references at least.
Patent trademark law in the U.S. does not discriminate as to national origin, so non-citizens may apply for patents. However, you will be required to swear an oath or declaration with each application, and you can't obtain a patent if your invention was patented abroad more than 12 months before filing in the U.S.