Does a degree in economics/corporate finance from an Italian university prepare me for a PhD in economics?
I'm in the same situation, so maybe I can help. The first thing many people don't realize is that many fields of advanced level economics are almost entirely math. Thus an undergraduate degree in econ may not be the best preparation for a doctorate if the degree is not very mathy. My university has a special doctoral prep program for econ majors for exactly this reason. You can see the degree requirements here to get a sense of how much math my economics department thinks you need to get a doctorate.

http://www.american.edu/cas/degrees/bs-mathematics-economics.cfm

My personal opinion is that depending on the field of economics you want to study (and how much math is involved), as well as the rigor of the doctoral program, you may want to take more math classes. Also while those are great core courses which you have taken, if I was an admissions officer, I'd be concerned about the grades. Take some higher math and show you've improved. 

To quote from one of my econ professors (a former central banker) "IF you come in with the math, graduate schools will have no problem teaching you the econ."

Courses you need:


Multivariate Calculus, Differential Equations, Real Analysis 
More Statistics, especially time series analysis.