The Windows installers are basically just executable zip files with some installer code at the front. They can be expanded using any unzipping utility like unzip in Git Bash/Cygwin/MingW32, Winzip, 7-Zip File Manager, etc. Once unzipped, just copy the resulting pyexiv2 folder to your virtualenv's site-packages folder, and you should be all set. The installer also includes two .dll files in a folder called $PLUGINSDIR, but I'm not sure where they should go, or if they're part of the installer. Don't do anything with them for now, and test the module to see if everything works properly. If it complains, hopefully the error message will give enough detail to figure out where it's looking for the files, and you can put them there.
Good luck!