Vandyrik

I've got what I think is a pretty simple question and rather than hunt the info down on admissions websites, I thought I might try here first. Here's the deal: I graduated with a BA in International Relations last year (May 2012) and have been getting some internship and volunteer experience before I send out applications for a MA (I want to start in the spring). A weak spot in my package is my mark for macroeconomics, so I would like to retake the course (or take another economics course) over the summer to offset it and show I can do the work. My question: is better to take the course for undergrad credit or for grad credit (pricier but I'm guessing I could get out of a core requirement at some programs)?