How do I transfer from Niagara college business sales and marketing to Mcgill commerce?

please help, still confused after two calls to mcgill admissions (and with the two hour wait on the phone it sucks to make a third call) I've been told I need an average in my college program in the 90s to be competative for acceptance which is understandable. They also said I will need two semesters of calculus (integral and differential ) to complete admissions requirements. How am I supposed to complete that at the college level? Any suggestions I will appreciate any advice!