Can anyone give advice about transferring money to pay for the property i am buying. How do i get the best rate for my money.

Hola, You need to shop around to see who will give you the best rate - you definitely want the Commercial rate as it is higher than tourist rate - try your bank and the currency exchange companies (HIFX, Currency Exchange) Look elsewhere on this site for more info which has been posted before.
May I suggest (just in case) before you transfer your money that you are 100% sure the property you are buying is legal and the person to whom you are sending it is legally entitled to it - once its gone - its gone!!

Hi there

I work for a leading Spanish bank so if you are still require help with this post, let me know and I will be happy to help.

Rgds
Manu