Are there any math or statistics electives that will better prepare me for graduate school?

If you are thinking of going to graduate school, then you should certainly take MATH GU4061: GU4062 Introduction to Modern Analysis (or at least the first semester of the class) and one of the year long sequences in probability and statistics at the 3000 level or higher (or again at least the first semester if you already have a 4000 level statistics class). Other good choices in the math department (but not as essential as the analysis course) are UN3027: Ordinary Differential Equations, GU4051: Basic Topology, GU4071: Intro to the Mathematics of Finance, and GU4081: Intro to Differentiable Manifolds. In the engineering school you will find IEOR UN3106/GU4106 Intro to Operations Research: Stochastic Models and APMA GU4101 Introduction to Dynamical Systems.