Sorry to hear of the accident.
Dont expect them to be cheap! Also fit them VERY carefully! They are explosive devices.
This brings me to my next point, As explosive devices, It is an offence to send them through the post, most couriers wont touch them so narrows your search.
If you have never played with airbags, I wouldnt recomend fitting them yourself
. You can loose limbs to them! HIGHLY dangerous!
As your asking how to do it, This would lean me to say DONT ATTEMPT IT YOURSELF.
a renault breakers such as http://www.renault-spare-parts.com/
would be worth a call/email.
May need a dealer reset on the
. TO have triggered the airbags, That must have been some whack, What did you hit? Are the chassis legs straight?