Sounds like you'll need to actually go to antarctica...
Failing that you could most likely use photoshop to create several backdrops and use a 3d modelling/animation program along with motion tracking software to create an ice bridge, don't expect someone else to simply provide you with these things. It's your movie so you need to be responsible for realising it.
Give this trailer a watch :http://fxhome.com/cinema/info_cache/movieinfo2091.html
It has some excellent CG sets, I'm sure it could give you some ideas. As for snow falling, that's something EffectsLab is more than capable of. By the time you need it, I imagine some snowy weather presets will be in the library.