How to get a metadescription to show in Google search

Hello,
I am trying to get my metadescription to show up in Google search results. My site is http://www.swimquest.uk.com – I have tried adding the below code as advised on the meta page on wordpress to the header page, however this isn’t making any difference.

<meta name="description" content=“SwimQuest offer incredible swimming holidays, suitable for all abilities, in amazing locations worldwide." />

Can anyone help / tell me what to do to ensure their is a description under my google search results?

Thanks
Alice