Didn't see this before!

I suggest :

1. Change your video renderer to madvr, though only recent mpc-hc and kmplayer build support this, it will (imo) give most visible gain to PQ.

more info :
madVR - high quality video renderer (GPU assisted) - Doom9's Forum. I suggest using version 0.9 as 0.10 and 0.11 have annoying bug, you can get it here madVR - Video software and downloads - VideoHelp.com.

2. Learn to use Avisynth, the array of filters available is very powerful and with your config it'll be no problem using it realtime.

A good guide can be found here upscaling standard dvd movies to 1080p using ffdshow and your htpc - AVS Forum. Seesaw and limitedsharpenfaster is especially good for movies imo, and there are also different config for anime.

 

probably you'd want to try this too: frameinterpolation for superfluid smooth ... (from 24 fps to 48 and so) it uses avisynth
works not only in 1080 mkv's but also in almost every size/format that uses ffdshow.
Frame doubling interpolation for 1080p x264 mkv's for superfluid 48 fps - Guru3D.com Forums
and it works like a charm!!