1. the difference in traffic between #1 and #2 isn't much, in fact I've had some sites be more productive in #2 then #1, as long as you are above the fold you are good. i would however take #11 over 8-10. the descript Google shows below your site is much more important then being 1, 2 or 3.
2. changing the design is stupid, if its working now and you are well ranked, leave the design alone!
as for the advice you asked for... try to optimize deeper pages on the site to rank more preggo related longtail terms. let the site float and make money, youve already reached the top, enjoy it. screwing with it too much might topple it. id take what you learned and apply to other domains/terms.
when you first get to the first page you will see a lot of movement, sometimes drastic. 30+ position movement from hour to hour. after a while you will settle into your spot though, if that ends up being below #2, then i would think about making small changes to try and move up a bit.
from a guy that doesnt know SEO
