Wifi Extender to use w/ Phone?

[GeminiTroll]

I've recently started an internship with a private ambulance agency and between calls we tend to find ourselves posted in various shopping center parking lots. We are usually just on the edge of WiFi access for my phone and I have trouble keeping a connection. I'm looking for a wireless extender (or some other solution) so I don't eat up my data usage on slow days. One of the other guys uses a laptop for Netflix without problems, so I know the actual signal is strong enough, I just need it boosted for my phone, or maybe an external antenna if those are any good.

I have AC outlet access on the rig and I'm using a Moto Droid X. Any suggestions or recomendations would be appreciated.