Where can I take an easy Microbiology class (prerequisite for nursing) in the inland empire or around the area?

You will need to see what CCs close to you offer this at a time you can take it, but you are running out of time to get into a class for next semester. You will need to do the leg work here, as it is going to take time. Look for micro specifically for nursing (not the bio major one) if there is one.

I've never taken microbiology, but I'd heard that it's a challenging course.

This website has U.S. colleges (including community colleges): http://www.utexas.edu/world/univ