Macro to copy data under appropriate heading

Hi,

I've attached a spreadsheet of what I'm working on. I have 2 tabs, "Sheet 1" (which is where I want to execute the macro) and "How it should look like" (after the macro has been executed).

I'm trying to create a macro that copies range A18:A20 under the appropriate heading date in "Sheet1". For example, if the month is September 2013, I want it to copy the cells into C2:C3.

You might ask why I'm not using a lookup function. The reason is that this is only a small scale example of what I'm working on. At the start of every new month, cell A17 is going to change, but I still want to be able to have previous months' records. So for example, in October, cell A17 will be October 2013, but I still want to keep September's values. Like I said, this is a really simplified example of what I'm working on.

The script I'm working on is shown below. I've just started playing around with VBA a few days ago, so this is all sort of new to me. Any assistance as to what I'm doing wrong would be appreciated.

Sub CopyPaste()
Dim I As Integer
I = 1
If Cells(1, I).Value <> Range("A17").Value Then
I = I + 1
ElseIf Cells(1, I).Value = Range("A17").Value Then
Range("A18:A20").Copy
Cells(2, I).PasteSpecial
End If
End Sub

Thanks

Sample.xlsx