Excell Asset Allocation Model

I need an Excel Spreadsheet that can Do Asset Allocation Modeling. Specifically Standard & Poor ( S &P ) and Barclay AGG index I want the spreadsheet to display month by month gains/losses in dollars and percentage of 1 million dollar with 5 percent deducted each year. The 5 percent has to be taken out evenly each month so 4166 a month. I want to be able to do any Blend of Equity and Bond( example 50% Equity and 50% Bond or 75% to 25%). It's pretty simple stuff and I can provide data if needed.