A few points to consider:
Rent Supplement may not be approved for a single person in a house (assuming it's got more than one bedroom of course), as the person may be considered over-accommodated.
If the rent being charged is greater than the maximum rent limit which applies to your county, Rent Supplement is not payable.
If Rent Supplement is granted, you are required to pay a minimum of €18 per week towards the rent from your Jobseeker's Payment. The jobseeker's payment itself is not affected, you will continue to receive 204.30, you just have to pay the minimum contribution to your landlord.