Hi. I am in Mora D'ebre and work from a Vodafone dongle. We have windows 8. The problem we find with Vodafone is, No matter how much or little we use it a month, We can only get dial up speed for the last 7 days of the monthly contract. ( speed always come back to normal after midnight on new month ) Perhaps your download of windows 8 used all your allocated speed allowance, and the speed will improve when you start the next months rental period.
There is a internet Café on the top end of Mora high street almost  opp the high school called Café somnis. not always reliable for opening times or reception, but when it works is ok. good luck.