Can some one let me know how to draw a graph in AutoCAD (Ex. Road longitudinal profile) using x,y coordinates given in a Excel spread sheet. And also to retrieve coordinates from the drawn CAD graph to a Spread sheet  

You can paste X/Y coordinates to the PLINE or SPLINE command or you can use LISP tools for this. We have e.g. the Xls2Curve utlity - see:http://www.cadforum.cz/cadforum_en/simply-create-points-or-polyline-from-coordinates-in-excel-tip6692or 2DPlot (if your points are generated mathematically) - see:http://www.cadstudio.cz/en/apps/2dplot/