is the child going to be living with you? if not then your not entilted to one parent family allowance.
if you want to apply for rent allowance you need to be privatly renting for 6 months before you can get anything. if the child is not going to be living with you then you may only be entilted to rent allowance for a room only unless you can prove that you will be having the child over nights on a regular basis and need a 2 bed place, but many single fathers have found it difficult to be awarded this. when recieving rent allowance you still need to pay a portion of rent (€24 a week in my area!)
your best option may be to try and stay at home untill you find work and can afford to rent a place as you will also have to pay your ex child maintenance to support your child. it dosent matter if your working or not.