|You want to replace whatever is in B649 with =TODAY()?|
Are you aware that =TODAY() is Volatile and will update every time the sheet calculates, including every time you open and close the workbook?
In other words, what is displayed in B649 today will be different tomorrow, and the next day, and the next, etc.
In addition, put enough =TODAY()'s in your spreadsheet and you'll slow it down since they will all recalculate at the same time, every time.
1 - You can't place a value in a cell with an Excel function. An Excel function can only return a value in the cell in which it resides.
If you want to place a value (or function) in a cell via some "automatic" method, you'll need to use VBA.
2 - How are you returning a cell address? Can I assume you are already using VBA, perhaps a UDF?