First of all, thank you all for your help. Sorry if this is a repeated question but I have not found the answer.
My case is that in the blog page (http://www.fxeducacion.com/blog/) I do get the sidebar as I wanted (still improving it, but thats more or less how I want it).
However, when I click into any post of the blog (ie: http://www.fxeducacion.com/2013/09/03/analisis-y-operaciones-para-los-proximos-dias/ ) the sidebar is completely different.
The question is, how can I have the same sidebar in the post as I have on the blog?
I've work around and tried all the options but could not figure it out.
Again, thank you all for your help!!