You should take 3450:421 Advanced Calculus I and 450:422 Advanced Calculus II as electives in this program. Then you need:
3450:355 Introduction to Ordinary Differential Equations
3450:427 Applied Numerical Methods I
3450:428 Applied Numerical Methods II
3450:436 Mathematical Models
Total: 12 additional credits
Minor: You'll need only one approved 300/400 level mathematics elective.