Can you apply for colleges AFTER you graduate?

You really aren't going to have much of a choice here; applications for 4-year schools are due in the fall and early spring, so you can't do anything to your GPA that will make them consider you. Raise it as far as you can and plan to start at community college. Keep in mind your GPA in high school is failing by college standards, and college classes, even community colleges, are a lot harder than high school. It's really too late to fix this at the last minute.