this can be easily done via git commands
reset to selected revision: git checkout COMMIT_SHA -- file1/to/restore
reset to first-parent revision: git checkout COMMIT_SHA~1 -- file1/to/restore
mutiple files also supported: git checkout COMMIT_SHA -- file1/to/restore file2/to/restore
this is very helpful - you can go back to a bad commit.. select the file you want to revert, and reset to first-parent - this will efficiently restore it to a good state - next phase is to commit =]
this was the feature I loved most in git-extensions tool, but now I'm using mac - and your tool looks the most promising one!