How do I fix a light on my car? (Renault Clio Exp)?

I had my car serviced and MOT about a month and a half ago! Over the last few weeks a light has been coming on and off- il looks like a coil of wire with a box on top (in the box theres a line going through it). As well as this coming on and off occassionally on the right hand side of the dashboard the engine picture also comes on!
How urgent do I need to see someone about this? Not able to get to a garage till next week!

Lisa Evans
July 2008