You are best off learning a cad program like Draftsight or Double CAD - both had free versions. I now use a program called BricsCad but is not free. It is very much like AutoCAD that I have used in the past.
Some like CorelDraw but personally I don't and fine most files sent to me created in CD or Adobe have incompatibilities. No doubt you can sort them out but makes for a longer learning curve if you do not already know them.
GIMP is a good program for raster files - also free.