If you wish to tweak some more settings or even move your Google index, you should install TweakGDS. This is a small plugin utility that allows you to:
- change the index location
- adjust the number of results returned in a search
- add or remove indexed drives etc
You may also want to check out Halftone Search. This gives you a GUI shell for Google Desktop Searching and sorting of results. However, this is trial / pay software.