Blue Falcon

So far I've used my Meridian Platinum in my Saturn and in my GM Venture (mini-van). I get fine reception in my Saturn, which is good since it's what I normally drive. However, we use the mini-van when geocaching on the weekend since we're hauling the kids and the dog. The problem is I see the satellite reception drop drastically as soon as I bring it into the car. Since the Platinum doesn't have an external antenna, I'm wondering what my other options might be to get good signal.

My monitor works fine.

Are there any online maps (like mapquest.com) that would allow me to input lat/lon and get a map from that?