Please use a reputable travel agency. Such an agency will sort out your visas even before you leave your home. You don't want to be:
1. sent back to the US before getting on the connecting flight to your final destination;
2. be stuck at some immigration office for days and/or
3. end up in some detention facility for weeks on end in some country where nobody speaks your language.
Let the professionals sort it out for you before you leave.
Edited by Pressie, : No reason given.
Edited by Pressie, : No reason given.