Try to phone the French Embassy/Consulate, and ask for a Schengen Visa for your gf.
I think that she may have to go there personally. Cost...???I am not tooo sure, for now.
Ok, found it....
It is all explained here.....
http://www.ambafrance-uk.org/Visa-we...he-French.html
Just follow the relevant links....
Ciao