Making it visable and multi-lingual

Hi,
I have a wordpress website to sell my campervan business in the South west of France.
http://www.vantripper.com/2011/ It has been going for 2 years and so far has just about created enough clients (mainly from the english market). I am new to this as my site was set up by a friend, and until recently I pretty much ignored it (i assumed it was in good hands). We have recently increased our fleet and therefore need to make more sales, and when i checked our search results in French and english I noticed just how terrible results are..
I know that the french version really need improving, but this is becoming quite complicated (i cant get the language selector on the homepage).
I would like, if you would be so kind, your honest opinion of my site, and any tips for the functionality, but most of all SEO, if you could reccomend the best place for me (as a newbie) to go and learn/ read about how i can achieve this?
Many thanks!