Need advice on website ranking top 3 for $60-$70 CPC keywords

[urljunky]

I am a Plumbing contractor and i developed my own web site. In 3 months i was coming up on top just below yelp. It's based in Huntington Beach, Ca. Competition is extremely high. It's ranking in the top 5 for more then 10 keywords having to do with "plumber huntington beach". they range in cost per click from $73 to $38. So my question is, is that usually hard to do? It seems like these other companies spent a ton on their websites and are getting mediocre results at best. I put a ton of time into the site but not a ton of money. Second question is my site worth anything? Or just to me? I get plenty of calls every week and have had over $30k gross sales in the last 3 months, but i think i'm over my head and want to sell the site and company, which the site is pretty much the company. How much would it be worth and how would i go about selling a 4 month old website?
The website is Xclusiveplumbing(dot)com. What are your thoughts and opinions?