I have the xinput1_2.dll in the steam.exe folder location (no fallout new vegas.exe except on desktop) then i have the x360ce.exe there too and an x360.ini file too but no config file.
It needs to be in the folder with the FalloutNV.exe, not the steam.exe
I see you also got version 1.2..
use http://www.tocaedit.com/IB/index.php?automodule=downloads&showfile=4 (1.3)
or http://www.tocaedit.com/IB/index.php?automodule=downloads&showfile=44 (newer but without instructions)
Place it in the folder i wrote before. Program Files\Steam\SteamApps\common\fallout new vegas