Renault Megane Expression won't start?

We have a 1.6 renault magane expression and originally had the problem of car starting up with card and then conking out if no revs were applied. Then even after the snow in last week car was fine until last monday when card would go in and click in acknowledgement of it but no joy so car was bump started and when we went back out to go down to garage it started perfectly. Come to it again today and nothing, it still clicks to show its recognised card and lights come up on dashboard but no faults. We had sensors under clutch sorted few weeks back which has been fine as car wouldnt start at the time unless clutch, break and start button were pressed. Any ideas as we are pretty broke at minute please help!!

pregnant and need car fixed incase of the inevitable!