Your twin references to 'noise' and 'blurriness' have left me a little confused. If you scan your images you can use the filters within a decent image manipulation program to either:
a) increase the 'sharpness' (but at the expense of creating some additional 'graininess' in the image ; or
b) 'despeckle' (which reduce the graininess but can add a bit of blurring at the same time).
(You can't easily do both things at the same time but 'sharpen edges' and 'despeckle' used together sometimes get close to it).
You can, of course, change the hue, saturation, colour balance, contrast, brightness. and many other things as well, in order to improve the quality of the picture.
The best software (by far) is a 'full' version of Photoshop, but that costs mega-bucks. GIMP is free and wil do many of the things that Photoshop can:
http://www.gimp.org/
(NB: Ensure that you download the documentations as well as the program! Both Photoshop and GIMP take quite a bit of getting used to!)
Chris