Chari-Bichari,
Do you really want to divorce? You said you are looking for changing F2 to F1 or to B1/B2. Your plan to change status to F1 sounds reasonable, but what are you going to do with your B1/B2 status? It is better to prepare for TOEFL as soon as possible and apply to a community college where you can pursue degrees at the cheapest tuition. I cannot suggest you to go back and apply for college after your TOEFL is done. That might be risky. If you have someone in mind, other than your husband, get him as soon as possible.

I am sorry to hear about your decision to get divorced, but after-divorce life is not sweet at all.
Goodluck!

Bhatiza