How important are quant courses during undergrad?

[marid]

Long story short: Went to a grad school fair and a few of the schools I spoke to (Ford, Heinz, Harris) all said that quant courses are important when applying for their schools.

 

Now, my current experience doesn't involve quant skills at all and during my undergrad I didn't do so well on two quant courses(C's) the rest of my other quant courses, however, were much better (b's). 

 

Would this adversely affect my app to a top school? Looking into Ivy Leagues (all except HKS and WWS) and other top tiered schools. The admissions people said if you're worried about your quant background,take some courses but due to my time constraints and working 2 part time jobs, I don't know how well I'd fare in online courses.