Renault Clio 1999?

Hi
I have just bought this car and the speedo works when it wants to, I have noticed that this seems to be a common problem, only thing is that when the speedo stops working my heater plug light and injection light comes on too! Is this because of the speedo issue?as it goes off when the speedo starts to work, has anyone else experienced the same issues? Do I need a garage or can this be repaired?