I've been using DXFLib for DXF parsing (available here
I think it can read correctly any DXF from 2007 to 2012...
The graphic part is incomplete, I've been handling the basic entities (line, polyline, arc, circle,...) but the list is quite long. I actually use it in my apps after cleaning and exploding my drawings (ACAD commands EXPLODE and PURGE)
Take it as a starting point, it's not a CAD neither is a complete project.