Hey.
Yeah, zombie apocalypses are pretty common, so I might recommend adding some big twists in there to make it good - turning the genre itself on its backside. Work with the seemingly obvious cliches. It's your novel, but working with this - I'd try to make the main character a genre-savvy person who thinks she knows what is going to happen based off other zombie apocalypse movies. Of course, this is where you make the big changes - making the protagonist unsure of herself.
Flat out lie to your audience--if you like--about some of the events in the book. Otherwise, make the audience uncomfortable - it is a horror based novel, isn't it? The fact that the main character herself isn't so sure of what's going to happen anymore should work to the effect of making the reader uncomfortable.
Just my tibit of suggestion. Like Loki says, It would be better to read it, but I understand copyright and all.