For computation my preferred tool is the combination of R and C++.
R allows high level treatment of the data using the most up to date statistical techniques.
C++ allows to carry heavy computation extremely efficiently. Getting the two to talk to each other is made trivial by the excellent package Rccp and al.
Here is the selection of my open source projects:
no HPC at your university?
No reason to panic, you can always rent computers from amazon. This service is really amazing and you can rent an 8core machine at about $0.07 an hour. I highly recommend using the MIT project StarCluster. You will have your very own cluster within 15 minutes, and you can stop and restart it on demand. The EC2 service even has GPU cards for rent.