You can either stain your gel with coomassie blue or silver staining. Analysis of your gel could be done by ImageJ or GelQuant softwares for quantification.
If you just wanna calculate the band density, you could use ImageJ as it is pretty simple; however, if you wanna calibrate protein molecular weight and protein volume to standard...etc, u can use gelAnalyzer or PyEIph. Both of them provide functionality that ImageJ didn't have it.