Macro to transfer data between sheets...

Hi all! I'm stuck (Yawn... again? Yes.)

Attached is a spreadsheet to eventually generate invioces...

Monthly Data sheet:
This is where data is entered by individuals, they enter the number of hours they spend on a particular project in a particular month. This calculates the amount chargeable.

Invoice Data sheet:
This is a summary of all the costs that are invoicable.

I need a macro that transfers all of the invoiceable data from the Monthly Data sheet to the Invoice Data sheet in a list with no spaces. Column Y dictates whether or not a row is invoicable based on a number of criterea. The trouble i have is that rows and columns are added in order to add projects and staff respectively. I have tried to use Names (as you can see in the sheet) but struggle to use them in VBA. Anyone be of any help...