Here is a map of the DCU campus, which is located between Collins Avenue and Ballymun Road. (Here is a map of the general area.) The most useful entrance is on Collins Avenue, as shown. Make your way through the building works, turn right and park in the multi-storey car park.
To get to the School of Computing building (marked) you will have to go round the end of the Dublin Business Centre and round the end of Block 1 to get to the entrance to Block 1 Extension.
Scroll down (or click on the link) to see the floor plans of Block 1 and the Block 1 Extension
The School Office is on the First Floor, just near the head of the stairs. There you will find the School Secretary, who should be able to find me.