It\'s relatively easy to import a certificate into the user\'s personal store from a pfx file by using CertUtil:
certutil –f –p [certificate_password] –importpfx
Check these links: http://www.orcsweb.com/blog/james/powershell-ing-on-windows-server-how-to-import-certificates-using-powershell/
Import-Certificate: http://poshcode.org/1937
You can do something like:
dir -Path C:\Certs -Filter *.cer | Import-Certificate -CertFile $_ -StoreNames AuthRoot, Root -LocalMachine -Verbose