I only need to take one class online to get obtain one credit, who offeres that?

Try going to the dean or whoever or even talk to one of your professors find out who is in charge of decission making with credits and grades. Ask this person if you can write a paper or do some sort of extra study to earn one credit. Maybe intern for a couple of weeks. Sometimes they will do this for you beings it is only one credit. Go talk to them it won’t hurt to try