HiJaak is a program that reads over 100 formats and converts between them. It also has a raster-to-vector conversion which would allow you to generate a .dxf file, which you could bring into a sketch like an AutoCAD drawing.
If you have Adobe Illustrator available (try Kinko's), you can use it to convert vector components of .ai, .eps, and .pdf files to .dxf for use in CAD programs.