Yahoo's program doesn't garantee a ranking! It only garantee's that your site will get crawled on a regular basis and that your pages in their index will be recent. It is very good possible that your pages will rank low in their result, doesn't matter if you pay.
If you are allready in #1 position, nothing needs to be done: you are in there allready and on a high spot. Considering that you're ranked high, you will probably also get a reasonable regular crawl on your site :) for free! :)