Sorry but with all the CAD systems I'm familar with (AutoCAD included) you can't open future versions just past ones. I think you're hosed unless you can get access to AutoCAD 2007 or newer and then you can save them down as the 2000 release file format.
Plan B would be to go get draftsight it's a free autoCAD clone released from the parent company of SolidWorks that might do the trick for you.
Plan B would be to go get draftsight it's a free autoCAD clone released from the parent company of SolidWorks that might do the trick for you.