Looking for a freeware statistical computing software?
A nice R course on Coursera and the built-in Swirl tutorial can help you get started with R. My favorite R introduction; not fanciful dressed but to the point.
Interesting online resources about impact evaluations
International Initiative for Impact Evaluation (3ie)
Impact Evaluation in Practice: A useful guide to the conceptual idea of an impact evaluation. Non-technical, easy read.
A more technical approach to impact evaluation: Handbook on Impact Evaluation: Quantitative Methods and Practices