Hi,
I am not KwLee but am a grad student in economics. As you probably know, there is a big gap between undergrad and grad studies as far as economics is concerned. I believe that this is true for other sciences as well. Thus your intention of taking courses to prepare for grad school is a very good one.
To some degree one can think of Economics is a subject that can be classified or more precisely very closely related to applied math. As such, the stronger foundation in math you have the better you prepare for the first year in grad school in which you are basically required to take Math+Micro+Marco+Econometrics. Depending on how rigours the school you are in, but it is always a good idea if you can take the following courses:
1. Multivariable Calculus
2. Linear Algebra
3. Real Analysis (very hard but very helpful in Micro theory)
4. Introduction to Mathematical Statistics
Also, if you are attending grad scholl this fall you can photoread the textbooks that are use in your program. That is certainly the best strategy for getting a head start.
I hope this helps. If you need any further questions please post on this forum.
Good Luck!
Quang
