Renault Megane 04 plate hatchback?

I have a card reader error (fails to start - connection a bit loose but always manage to get going - until yest when i had to get a tow back) which has been intermittent for a month or so, i read there is another way (key inside the card reader) which goes into another place in the car to start it I couldnt find where it goes..
My steering wont unock unless i get it started and need to move from where i left it last night - is there another way.
If the key inside is not for here for that reason what is it for?
Also i can see a cards reader looks like the one I need on ebay - how do i know if its the correct one for my model etc