Low poly curve to a high poly curve ? i want to make this set of faces more polished , more round , just having more faces forming a more defined curve

normally i do a subdivision with the modifier and crease the faces from top and below but the model is too complex for that 

how am i supposed to do ? 

temporary file link:
https://we.tl/t-r7BXMT7Vxd

thanks
Your topology is not good, therefore it limits the improvements you can make. But you can make that corner much rounder with bevels:


Go in Edit mode > Edge select mode.
Select the edges of your corner.
Press ctrl B and drag your mouse.
Press + or - or scrollwheel to increase or decrease the amount of edges of your bevel.
Your corner is rounder.