Export R plot to shapefile

I am fairly new to R, but not to ArcView. I am plotting some two-mode data, and want to convert the plot to a shapefile. Specifically, I would like to convert the vertices and the edges, if possible, so that I can get the same plot to display in ArcView, along with the attributes.

I've installed the package "shapefiles", and I see the convert.to.shapefile command, but the help doesn't talk about how to assign XY coords to the vertices.

Thank you,

Tim