The shortcut should already be there from the 30fps unlock. I don't think your doing things properly.
The shortcut target path should look like this, for res scaling, NOT fps fix. You won't see frames above 30 with it enabled anyways. Copy and paste it if you want, as long as the drive path is the same as yours.
C:\Program Files (x86)\Need for Speed(TM) Rivals\NFS14.exe" -Render.ResolutionScale 2.0
Also make and put that txt file in the root folder as well. Won't hurt having both. And, instead of staring at the cars in the garage, load up a spot on the track in game.
You might get a game crash and that will be because of the 1GB vram your card has. It uses 2GB+ with res scaling set that high.
Edited by Slightly skewed - 11/26/13 at 1:40pm