The program and resolution have nothing to do with a picture looking washed out. Higher resolution just means the picture will be physically bigger to look at (and a bigger file size).
You will need to alter the picture after it has been scanned to make it look "normal".
You will need to change the levels of shadows or colours in the picture, and that is where your image manipulating program comes in.
The best tool at your disposal, imo, is the curves tool. Use of that can be read about here: [link]
You also might want to try "auto level" and "auto contrast"
Try searching DeviantArt's tutorials: [link]