Controlling Content Approval in custom SPD workflow

Question

I've designed a custom workflow using SharePoint Designer 2007 on MOSS 2007 to perform the following:

1. User uploads a document to a document library.
2. Workflow triggers and waits for designated Approvers to either Approve or Reject the document.
3. IF REJECTED, the user that uploaded the document is sent an e-mail and the document is deleted from the document library.
4. IF APPROVED, the document is moved to a second, "secured" document library.

This all works fine except for one thing. I want to record in a custom column who actually approved the document. As the workflow starts as soon as the document is uploaded to the document library then the workflow is running under the context of that user - not the user who approves or rejects the document.

Does anyone have any idea how I could capture who approves this document through the SPD workflow?