Excel 2007 : Using Excel for Accounting/Tracking Purposes - Need HELP!

I run a small office that tries to keep track of our receivables with excel (using both excel 2003 & excel 2007). Basically, each client gets an excel spreadsheet which tracks how much they have paid, how much work has been done and how much money they have left on their account/how much money they have exceeded their account. I started an excel spreadsheet that references cells which have (1) the clients name, (2) how much they deposited with our office & (3) how much they have left/owe our office. For purposes of this example I have called this “Master List”. Each client is linked to this master list from their original/own excel invoice.

From this information, I want excel to copy and paste certain clients and their information to other sheets contained in the same workbook. For example, I want excel to look at the “Master List” and in a new worksheet tell me all clients who have exceeded the initial amount paid by $500.00.

I started this using the sort function but it seems like there must be an easier and most efficient way. Any suggestions?