Need help naming this movie?

I saw this movie last year and I forgot what it is called. me and my friend have been trying to think of it and we have no clue what the title is. the plot is that a disease spread throughout ireland or some country like it, so they quarantine the infected place off for years behind a huge metal wall with guns and stuff. they send in a small team of soldiers to go check it out and there are people living in the quarantined area, but they are anarchists or somthing, with mohawks and dirtbikes. it turns out that the main character is one of the anarchists sisters or somthing and when they go to the countryside, there are castles with people living in them. near the end, there is a good car chase. please, will someone remember this movie and produce its title please? and also, the movie was made in between '05 - '09