ATPDraw is the answer... solves any power system network you can create.. allow transient analysis.. and in transformers.. it has already some models you can use.. but you can also design your own..for instances,  It's not difficult to find good examples in transformer implementation..

Matlab is a powerful tool for undergraduate students. It allows a quick start in programming, the language is well suited to represent engineering problems and it provides a quick verification of results with several graphical user-friendly functions.

I would recommend you StatSoft, Inc. (2011). STATISTICA (data analysis software system), version 10. www.statsoft.com. From my point of view it is an extremely powerful software.

Regards!