Homepage appears then disappears from google...(noob qu.)??

Hi, (yes I'm a noob!)

I'm think I'm experiencing what people call the 'google dance' but i'm not exactly quite sure what's going on, my homepage seems to appear then disappear from google. Let me give you an example (not using my real keywords):

Keyword: 'buy footballs' - some days my site is ranked between 12 -17 with this page being the homepage, yet other days it is ranked 200+ with the page being an inner page of mysite....

Keyword: 'buy orange and yellow footballs' - is sometimes ranked top 10 with the orange and yellow footballs page, yet sometimes it appears at number 100, with the homepage showing as the first page ranked.

The strange thing is, this occurs at the same time. The homepage is not be ranked for the main keywords, yet its ranking for one of the secondary keywords at exactly the same time.

EDIT: I'm based in the UK, but have my site setup in webmaster tools to target the USA, yet in google UK the first ranked page for the main keyword is always the homepage, but on google USA it is as stated above. Secondary keywords on google UK also experience the same thing.

Is this justa google dance?

Thanks.

It's google dance, be patient and continue to build quality links

Thanks for the response.

I outsourced some SEO when I set the site up, which took me from nowhere to being ranked fairly well, but I'm currently using the info read on here (Which is immense!) to do my own web 2.0 based SEO strategy.

Thanks.