Take the classes. If you don't do well, post bacc is an option, though they're really designed for people who haven't taken pre-med requirements at all.
GPA padding isn't exactly looked upon favorably among adcoms, if its obvious that you're doing it.
If the teachers "suck," do what you have to do outside of class to make up for it. Most adcoms are going to wonder why your non-science GPA is almost a full point lower than your cumulative GPA. It should be similar or higher to show that you can handle the classes that med school offers.