Divorce Question Please Help Me.?

I had caught my ex cheating on me, which resulted in me moving. Once I had settled in, found out that she had moved as well. I do not know her address, nor how to contact her to serve dissolution of marriage papers. Can not afford a lawyer, is there any way I can get this divorce. I also now live about 2,000 miles away from her last known whereabouts, and can not afford to travel there for a divorce hearing as well. Someone was telling me about that I can run an ad in the legal section of the paper where I last knew here to live. Could anyone shed any light into this idea, is it legal, and how long does the ad haft to run for?