Gretish is right but you deserve congratulation because this is you main business and not many people can say that they are on the first page for their main business keyword...
just chage your keyword,, you have to work on like "earn online" that type of keyword.. then you have get more traffic
Well done mate, now just do some more keyword research and find some of the high traffic, more competitive keywords and work on getting those ranked also to increase ur traffic and earnings. Essentially even though u are ranked for a low comp keyword at the moment it still adds credibility to your site as far as Google is concerned so you can not leverage on some of that credibility by targeting higher comp keywords.. Good luck and well done!
Not really a competitive keyword to be tight on the rankings. Anyway, congrats with this. Hope you maintain its rank.