Finding accommodation in Dublin can be difficult.
Temple Street Children's Hospital is in central Dublin, also known as District 1. Rents in central Dublin can be expensive, so it might be best to consider areas farther away. Traditionally, rent is cheaper in northern Dublin.
Do you mind living with other people? This might help you find a place closer to Temple Street.
The bus system is extensive but can be slow during peak traffic hours. Cycling is increasingly popular and Dublin is surprisingly small for a capital city, so you might be able to find accommodation that you can easily commute from.
This Expat Arrivals page on getting around in Dublin might provide some insight into Dublin transport.