Punctuation in Outlook 2010 displaying incorrectly when sent

Hi,

When typing a new message or a reply, some symbols and punctuation characters appear wrong when they are received, and also in my sentbox. The email, when typed looks fine, the problems begin when the send button is pressed. 

For example: 

The typed email reads as follows: 'I'm in the shop and I have €300 to spend.' (no error there)

Once sent email reads as follows: 'I’m in the shop and I have â‚¬300 to spend.' (error on the ' and the '€' symbol)

Can anyone suggest a possible solution to the problem?

Thanks,

Damien