Your wife needs to be accepted to a college, she needs to show that she can afford tuition and living expenses for the first year and she needs to show that she has strong ties to the old country and will return. If she is successful, she will get the visa. If you apply together at the same time, you will either be both accepted or refused. If she applies first, it may happen that she is accepted based on strong ties to homeland for leaving her husband behind but then you apply to join her, you could be denied based on being a risk to over-stay. If you are both accepted, you can get an open work permit based on her study permit.