Two things you might be interested in knowing:
1) Yes, there are post-bacc programs for international students. Keep looking.
2) You don't necessarily have to enroll in an official "post-bacc" pre-medical program. You can simply enroll in a University and take the classes you need or want without necessarily working towards a degree (this is also considered "post-bacc" by AMCAS). Post-bacc is simply an umbrella term for people that go to college to take classes after they already got a degree. The reason some programs are called post-bacc is because they tend to cater to career changers. Therefore, classes are typically in the evenings (after work) and are the classes you need for med school (such as organic chemistry, which is hard to find in the evenings). If that doesn't matter to you, you don't have to do post-bacc, you can enroll as a "non-degree" student and take whichever classes you need.
I hope this helps. If you need a visa to come study in the US, make sure that you contact the university's international office. They can give you good advice as to your options. You might not be allowed to come simply to take some courses. You might be required to be a full-time student and/or a degree-seeking student. Make sure you get all the info from the right sources.
