I see you have fallen prey for one of the 1000's of dating scams from Ghana. It is the most famous fraud on the internet ( just Google Ghana dating fraud) Also go to the US embassy in Ghana's web site and almost the entire site is warnings of dating fraud.

The passport and visa is about 300 dollars total, another 100 if rushed in about a week. Air fare can be done though a pre-paid ticket that they can not cash our.

So how much are they telling you they have to have in cash to get a visa ?