Can someone please help me with this task?

I have a workbook with 2 worksheets (W1, W2) that we use daily. At the end
of the day, my colleagues and I want to save W1 (only) separately.

Secondly, the file name used is the last unique number generated in that
worksheet (W1) automatically. So the file name will actually be a number
generated in that worksheet.

Is this possible?

Thanks!
Novicer.