We can never tell you "X points for doing Y". Impact isn't just about the change but about one's credit and how the change factors in. Derogs tend to have a significant impact and hold one's scores down but, again, the impact depends on one's credit and the specifics of the derogs. Even with every detail we can provide an educated guess. However, generally speaking, your credit is better if completely free from derogs. Those reasons are why addressing derogs are always recommended as a first step even if we can't tell you the specific score impact.
See also:
http://www.myfico.com/crediteducation/whatsinyourscore.aspx
Note that Payment History is the biggest slice. Your derog has an impact on that. If you have others then see what you can do about them as well. If you have not already, then take a look at the Rebuilding subforum.
