My setup is 3G by Millenicom/Sprint with Sierra 598U 3G modem. I am using a mobile antenna near a window on second floor. It works, however, I am also using a dual band signal amp since I want best possible connection. It looks like your UMW190 can accept external antenna. Your modems are 3G only, correct? It sounds like you're close enough to 4G that it might work with antenna system. If you know someone that has a 4G Verizon smartphone there are some apps that can help pinpoint the towers used. If it's safe, I'd even try the phone on the roof to see what kind of 4G signal/data performance it gets.
See what the neighbors/business use other than satellite. (I used to have Hughes)
There might be a wireless ISP that could work with line of sight system. They offer decent speed (Tall antenna may be needed, WISP companies may offer a survey for a small fee. They may also know if your area will work ahead of time.)
You could check with Verizon store if one is not too far for 4G. Check their return policy.
T-Mobile also offers a unlimited data package but it is pricey and may be limited to certain devices.
CLEAR offers WiMaX 4G but only near metros and they're not expanding coverage as far as I know.
There is a company called unlimited 4G. Somewhat like Millenicom. About all you can do is contact them to see if service is available.
I'm going to guess you're far enough away from DSL or Cable.