In my opinion the Nios 2 Hardware Development Tutorial is the best place to start (link at the bottom), mainly because it demonstrates the vital link between Quartus and Nios II IDE. I'd recommend going through the steps in the tutorial, and then depending on how hard/simple you find the process, you can consider whether you can do your project in 5 months...There are also several other tutorials in Nios II IDE specifically designed to help learn...
Hope this helps.
http://www.altera.com/literature/tt/tt_nios2_hardware_tutorial.pdf