Sorry about your situation.
Are you apppealing against the decision to refuse asylum, or something else? If you are already eight months pregnant, I don't think that you could be removed until a few weeks after the birth.
The facts of your need to be with your husband unfortunately is unlikely to weigh in any decision about an asylum claim. The BIA can argue that your husband could join you in Africa.
An application for a spouse visa would normally have to be made from your country. Did you marry in the UK, perhaps in the Church of England?
As for travel to Africa, your ARC is not important. You can always apply for another one, but you won't need it at the airport. However, you would need a passport from your own country, or some other travel document acceptable to your country. You could try contacting the IOM -
http://www.iomlondon.org/ - for assistance in getting a travel document.
IOM also give financial assistance to returning asylum-seekers, not sure how that would work out if you were planning to come back on another visa.
The Refused are coming day-by-day nearer to freedom.