I got a C+ in calculus-based physics I, and another C+ in circuits for engineers. I'd say the best way to make up for a C in a science class is to rock the appropriate section of the MCAT-- show the adcoms even though you may have dropped the ball in the class, that you can hold your weight with the subject matter on the MCAT. Also, increasing your academic performance over the next few semesters definitely helps. Raise that BCPM any way you can!
good luck!