i think i have to second what pretty much everybody else has already said. for an MSc in Statistics i think any potential advisor would try and see whether you have at least mastered the basics already (linear algebra, multivariate calculus, regression theory, at least some introductory probability theory, etc...) and, at least from what you mention in your post, all of these are areas where may still need to work a little bit more on. first year calculus just wont cut it in any (respectable) math department...

now... with that being said... i switched form an MSc in Statistics to an MA in Quantitative Psychology/Psychometrics... have you considered something like that? if your aim is to focus on social research, perhaps an MA in Research Methods, Quantitative Psychology, Educational Measurement, etc will both give you the exposure you need to advanced statistics while, at the same time, be able to speak the common language of the social sciences...