You can get huge rolls of clear plastic at most hardware stores to simulate the quick set up portable hallways you see in quarantine areas or disaster relief stations. Maybe lots of floresent lighting, bio-hazard signs and suits, flashing yellow lights.
Maybe a "clean area" that people have to walk through to get to the main area of the party. Jets of air come down from above to "disinfect" them before entering.
You can do the disinfection area by using the irrigation tubes found in the lawn irrigation section of the hardware store. Just punch the hose. If you wanted a mist instead of air, use the irrigation attachments. There are many different ones from misting to spraying.
Loved that movie! Is Timothy Olyphant coming to the party? You might watch the movie again, but this time with an eye for what would work in your house. The best scene was where the wife was tied to the gurney when they guy comes in with the pitchfork. You could create a room with plastic tarp on the walls. Get some collapsible tables as a gurnee with a prop person laying on it (maybe with a pitchfork stuck inside her).
The Help Us sign from the movie poster could go outside. For dress up guests, you need some people in sheriff/deputy uniforms. The deputy wears a flak jacket through the movie. Also a prop outside of the government people wearing their bio-hazard suits and gas masks. That could be accomplished with a cheap paint suit from Home Depot.
If you are coming up short on ideas, you might want to do a homage of several zombie movies. I did a zombie apocalypse party last year where I had rooms dedicated to different movies (eg. Shaun of the Dead, 28 days and Resident evil)