I've made a script to automate vrimg2exr work (requires python 3.2)
it's made to be used trough command line in windows (but in a few minutes you could use it under linux or os/x) typing "python vrconv_0.8.py namefile.vrimg"
If you've got more than one frame, you can use jolly character (namefile.*) and the script will find all frame in the directory, converting each one, extracting channels and renaming it ("namefile_channelname_framenumber.exr")
Use it and let me know if it's as good for you as it's for me :)