Your model has no parameters Creating Model Parameters ... it's all in the 'P' That parameter, the output filename, will take care of that since the model will enable you to specify a filename. currently your filename is extremely long and convoluted ...
( d:\Rok_Cedilnik\01_ArcMap\13_izracun_oglisc_raster\test.gdb\rtp_DOF_KRANJ_A1.tif.shp )
and ends with a ....tif.shp file extension and is located in folders that begin with numbers.. effectively breaking several naming convention rules.
As for the 2 Gb file limit... that is a shapefile limit, you need to use a featureclass in a file geodatabase.
At this point, I will let others that have been silently following the thread weigh in, I suspect that many of the issues you are facing are covered in the Modelbuilder Tutorials... so I would direct you to those since they do cover the basics.