How much to get me ranking no 1 on google

I think you should add more pages and work on High PR3+ backlinks..
I actually was impressed when my sites got to NUMBER 1 spot after doing this..
Every site has to have AT LEAST 5 pages..

This is what I think and in 7 months I got to 700 dollars/month ))

You currently rank #13

Getting to top is one thing keeping it is another.

Keeping the site As is would be quite a challenge.
Back links and content will help but you will need more than that to leep over established high PR/Popularity competitor.

My Estimate is at least $500. You could get 3-6 position easier but not with few fiverr gigs for sure.

You can do it yourself. Some article backlinks, linkwheels, blog comments. And you will get their.