Now, this service... how much does it usually cost if I needed to get a 18,000 mile full service done on it?
Ok lets get this clear you have no wanenlty if somehting goes wrong Renault rules weren't ideal 18k/2 years servicing was was to little IMO.
Personaly do a full good service IMO your cars near 4 years old so cambelt coolent brake fluid and then the normal servicing filters etc.
Renault rules etc are here don't forget some servicing rules by Renault were age not just milage rules.
Again Renault rules are for to lax IMO. Mine would have been
1 year 12k servicing with oil chnaged at 6k/6months.
60k/4 years cambelt should be done
2 years for full brake fluid
4 years coolent chnage.