how can i import autocad file in solidworks and how can i export 3d's file from autocad or solidworks?

type "export" in command line

Try Lithography - *stl file format.

ooo tnx mannn....and how can i export it to 3d model and render it?

Welcome. If you mean converting 3d model to *stl,then:
for SolidWorks : File > Save As > * stl
for AutoCAD: File> Export > Other Formats >*stl
Then,for example,3dsMax(I usually use this soft for my renders)
File>Import>*stl - this is for model exported from Solidworks.