sadundergrad

Hi, I'm currently a sophomore studying Economics and Statistics at a well known U.S. university. I'm interested in applying for Phd in econ (preferably top 20), and I'm well aware that math is a crucial part of it. I've taken math courses, and sadly I got a C in intro to proof and a B in probability theory, but otherwise As. I'll do my best to keep my grades up, but I was wondering - will such not so good math grades hurt me during the application process? Also, general advice? PLS HELP Thanks.