Help with After Effects

Hey,

I'm new to After Effects but I'm not new to a lot of the ideas in it. Have been using FCP and iMovie for some time now. Anyway, here is what I'd like to accomplish.

I drove through an intersection and videotaped it. I have a sign design that I would like to superimpose on to the corner of the intersection so you could see what the sign might look like while driving through the intersection.

I've tried for hours to make this work. I've got the video imported into AE and a vector art file (.eps). I've played around with the motion tracking feature, but can't seem to get it to work. Is there another way to do this?