You can install either (a) install binaries for both vagrant and virtualbox or (b) you can get them via the chocolatey/nuget package manager.
To install using precompiled binaries:
Install chocolatey.
Download and install chocolatey, you can get the installer from the Chocolatey website. Once you have chocolatey up and running, you can install vagrant and virtualbox using the following command
cinst -y virtualbox vagrant