Yes, its different material, but it makes you recall topics covered in Calculus I and II. The typical Calculus III course usually covers vectors and vector valued functions (something that should have been mentioned in BC calculus), partial differentiation, multiple integration, and vector calculus [and (of course) various applications].
If you don't take Calculus III soon, you may forget things. However, if you keep practicing the Calculus I and II stuff every so often, you might be able to wait a year to take the Calculus III course...its really up to you.
I would suggest that you take it this spring, even though the professor may be bad. You have a reliable resource in MHF, and we are here to help whenever you need it.