Well, the point of home security is to alert the authorities or you. This typically requires an Internet connection. Unless you're in a very rural area, you are most likely spending a lot more for that MiFi than you need to, primarily because of the data limits. Speeds can be good, if you're in the right area with the right carrier.
Anyhow, I would encourage you to look at getting regular Internet service if you can and then use any router you want. Does your MiFi not have a WiFi signal? If it doesn't, and it's a USB device, then you can use a Cradlepoint router to share the Internet signal via WiFi.