Combo Box Not Selecting Correct Record

[David]

I have a combo box that show many records from the same
vendor, If I select say the 5th record down from the same
vendor, My fields are always being populated by the first
record in the combo box, not the 5th,

My code is:
Private Sub CompanyName_AfterUpdate()

Me!CompanyName = Me!CompanyName.Column(0)
Me!SpicificUse = Me!CompanyName.Column(2)
Me!ActualTask = Me!CompanyName.Column(2)
Me!BidAmount = Me!CompanyName.Column(3

What do I need to get the 5th record to populate my fields?

Thanks
David