Sounds like you might be wanting to use a Table. Select your data, and hit Ctrl+L to convert your data to a table. After that, whenever you create a new line, all your formulas/formats will be copied downward.
Hi, Im not to sure what some of your cells mean but if your cost rates are the same for each room, eg labour etc, I would change the layout of your table to something like this. Some of these columns you may wish to delete, i dont know what they are all for but you will get the idea. If the cost rates are static then they can go in a table of their own. ps i use excel 2003.