wifi booster/antenna

I just bought a Linksys at Best Buy for $79. It does work, but I've got it outside, on top of my truck hood, encased in a zip lock bag (it's raining). If the wind were to come along and move it 1/4" out of position, I'd probably lose signal. Bottom line is that it's not a cure-all. Linksys has a $159 version, but the blue shirter told me I'd probably be satisfied with the $79 version; I'm not so sure. What pisses me off is I can see the wifi antenna about 150' away, with nothing in the way!