When should I have my period after having a medical miscarrage?

1-2 months. You should return to your normal cycles within a month or two. If you had regular cycles before, they should resume. However, now is a good time for contraception and this will dictate when you have your next cycle. (ie - depo-provera may eliminate your cycle, ocps may make your cycle regular and predictable, etc). Ask you physician for contraception that is best for you.
Varies. After a miscarriage, it an take up to 3 months for menses to return.
2-4 weeks. Really depends on how far along you were in the pregnancy. First off, I am so sorry you had to experience this. Secondly, what medication did they prescribe you to induce a miscarriage? It can take several weeks for your body to metabolize the HCG molecule (pregnancy hormone). It depends on how high (how far along) it was to begin with. Not unusual to have 1-2 mos before starting again.