All I can say is there was probably a reason you broke up...what was that reason? Did she tell you or did you figure it out?
What woul dhappen if you called her and asked if you could get together for coffee?
Of course she may say no, of course nothing may come of it. But, If you did the work on yourself to make yourself a better person for you...that will show through
doesn't mean you are the right person for her though